Island of Dwarfs and Giants

At about 50 thousand years ago, this is the Pleistocene Epoch of the Quaternary Period. What in the future will become the Indonesian island of Flores is already an island, though, everywhere else, the ocean has significantly receded to the point of connecting places like Borneo, Java, Japan, and even the British Isles to the mainland, though the continents have finally assumed their familiar positions we know today. These strange land connections are a result of the Quaternary glaciation, which started about some 2.8 million years before this tale and is still ongoing, even in the present day. This glacial period is a culmination of the cooling trends that, as we have observed, mount back all the way to the start of the Cenozoic. The most recent event contributing to it was the linkage of North and South America, which, by blocking the mixing of Atlantic and Pacific currents, led to the cooling of the American Pacific coast and, conversely, brought warmer waters to the Arctic through the Gulf Current. While this could be seen as a phenomenon against further glaciation, it actually helped it, as increased moisture precipitated more snowfall and even more ice growth.

However, like the Carboniferous ice age we explored many expeditions ago, this glaciation is also marked by the alternation of glacial and interglacial periods, defined by changes in the Earth’s axial tilt and orbital eccentricity. As explained then, the changes in tilt can expose the ice-covered areas to greater amounts of sunlight, which results in more cooling, since ice reflects much more than it absorbs. Once the tilt changes again, darker areas, such as oceans, may be the ones to receive more of the Sun’s rays, triggering warming. Regarding the changes in eccentricity, they might make Earth get closer to or more distant from the Sun, triggering episodes of increased warmth or cold, respectively. During the time of this tale, the planet is immersed in one of those glacial periods, one which will continue for some more 40 thousand years, about when it will give way to the modern-day interglacial period.

Now, it is time to focus on the environment we find ourselves in. Amidst a world gripped by ice, Flores might seem like a tropical refugee, with a reasonably warm climate and well-demarcated dry and wet seasons, a typical monsoon climate, which, itself, is a climatic configuration typical of tropical latitudes (as has been seen in various previous tales), occurring, in part, also thanks to Earth’s axial tilt, which is responsible for the seasons as we know them, determined by the amount of light received either by the Northern or Southern Hemispheres (the whole process behind monsoons was explained in much greater detail in our first Mesozoic voyage). The monsoons in this region are more pronounced than in other tropical areas, though: this is a result of the Himalayas, which block dry air currents from the north, causing greater amounts of rain. However, far from being a hospitable refugee, this fairly isolated piece of land can be a rather ruthless environment. Situated in a very geologically active area, it is subject to earthquakes, tsunamis, and volcanic eruptions. Not only that, but being a small island, it presents limited food sources, which are even more limited during the dry times of year. Consequently, the fauna that calls this piece of land home is quite peculiar. This island is full of dwarfs and giants.

The first animals we encounter seem to fit into the category of dwarfs. They are lizards 40 centimeters long, with slender bodies, large claws, and an ornamented pattern marked by black stripes and yellow spots amidst an overall yellowish base coloration. Their forked tongues flick in and out, taking in important sensory information from their environment, just as was previously established with Saniwa, observed here. Such clues are extremely important, for these, though tiny only temporarily, currently live in great danger. They are, after all, baby Komodo dragons (Varanus komodensis) and, though nimble in trees at their present age, they will grow up to become a few of the largest predators of this island, far removed from their arboreal habitat of old. The problem is that those who have already gotten to adult age eat basically any meat they come upon, including the youngsters of their own kind. As such, life is hard for these young squamates. Even so, they count on a few tricks, such as bathing in dung, a strategy that masks their smell with odors usually repulsive to grown-ups, and, as we can see, sticking to trees, at least most of the time.

From the trees, they can observe what goes on below and also secure their most important meals: arthropods and less fortunate, smaller lizards. One sight is not so rare for them to see, but also not terribly common either. They watch five other beings curiously and act skittish around them, for these creatures are also predators, but ones of quite a different aspect. Looking at them, we are struck by familiarity, but, at the same time, by uncanniness. Very much alike ourselves, but very much different in other ways. Perhaps what comes of most strange at first is their height: they are only 1 meter tall, but are not like children in any regard, clearly being fully developed individuals. A closer look reveals faces that are rather different from ours, with more robust traces. But, apart from that, we can say we are quite alike, with them even using accessories made from plant fiber and shells, widely available on the many nearby beaches. This is no coincidence, for these are also humans, albeit of another species: Homo floresiensis. These primates likely arrived here perhaps as far as 1 million years ago, potentially victims of a rafting event following a tsunami or maybe a particularly intense monsoon season. They are a small part of the great hominin diaspora that started in the distant lands of the African continent.

Like in many regions across the world, those African lands were also rocked by increasing aridity a couple of million years ago, at around the end of the Neogene (when our first exploration of Cenozoic South America took place). In their case, the drying trend resulted from a reunion of factors impacting atmospheric circulation. The first one was ice growth on Antarctica, and the second one was geological uplifting on the Eastern portion of the continent, marked by intense geological activity as a result of rifting plates. Both of these would lead to decreased penetration of winds into the land mass, causing less arrival of humidity and progressive aridification that, starting in Southwestern Africa, would spread to most of the continent by 3 million years before this tale. Plausibly as a consequence of these climatic changes, hominins appeared, some 6 to 7 million years ago, after splitting from their last common ancestor with chimpanzees and bonobos (Pan), our closest extant relatives.

Such new monkeys, the hominins, were not so unlike other apes in the beginning. But their more significant dwelling in open and savannah environments would shape them into quite a peculiar form as a result of new selective pressures. With time, some became more upright and, eventually, completely bipedal. This was not a linear process, however. Many organisms radiated from the ancestral hominin stock, some showing more typically human-like features and others bearing a closer resemblance to chimpanzees, some being more constant bipeds while others adopted a bipedal posture more occasionally, still heavily tied to trees in some ways. Such a mosaic of features was likely also due to several hybridization events, for these animals, though some more basal and others more derived, still coexisted and probably mated between themselves, originating a plausibly continuous spectrum of physical traits. Another contrast would emerge from their close chimp relatives in the form of behaviors. Like bonobos, hominins became less sexually dimorphic (evidenced by greater body and canine size in male chimpanzees) and males less antagonistic and territorial to one another, a change possibly associated with reduced levels of androgen (hormones such as testosterone) exposure during gestation and one which allowed for greater male to male bonding and cooperation.

The hands of a few, once with long fingers used especially to get a hold of branches, turned into their main weapons, allowing them to throw objects at other creatures and eventually even craft their own tools, enabling not only more efficient scavenging, but eventually the carving of a niche among the apex predators of the continent. A key physical adaptation would help ensure the success of these unusual primates, that being a vastly more significant ability to sweat. Sweating is certainly not exclusive to hominins, being shared by mammals and potentially an old trait, since ancient synapsids such as dinocephalians already had glandular skin (read more about them here). In this regard, most mammals usually have a much higher concentration of a certain type of sweat gland, called apocrine glands, heavily associated with sebaceous glands and hair follicles. The other type of sweat gland, called eccrine glands, is normally found in the soles of hands and feet, where they serve to increase adhesion (in New World monkeys, they are even found on the underside of their tails, a distribution justified by their prehensile quality).

In Old World monkeys (which include hominins), the eccrine glands are distributed all over their bodies and serve another function: thermoregulation. Unlike other members of Mammalia, which usually dissipate excess body heat by panting or by increasing blood flow to the skin, these tetrapods do so mostly by sweating and, in the case of hominins, the number of eccrine glands is even bigger than that found even in their fellow Old World monkeys. But how did these eccrine glands help hominins become predators? Potentially by providing a very efficient means of cooling, one which allowed such monkeys not only to live in hot and Sun-scorched savannahs, but also to run behind their targets for much longer periods of time without overheating. Consequently, even though their victim might run faster, it certainly could not do so for longer. This adaptation towards endurance running likely became associated with a loss of fur, as the lack of it would facilitate the loss of heat through sweating. Additionally, such sophisticated cooling mechanisms could facilitate traversing the open African environments during more sunny times of day, in which other predators would be absent due to the heat, providing more safety during those treks.

Apart from an increased ability to sweat and bipedalism, hominins also developed other novel features. Certainly, the most noticeable one was their increased cognitive capabilities, which were the main trait responsible for their great success and eventual colonization of all continents of the planet except Antarctica. A few mutations were likely instrumental for this development, such as the three duplications of the gene SRGAP2, which codifies a protein associated with neuronal migration, differentiation, and establishment of synapses with other neurons. These duplications were correlated with a rise in brain size and the number of neurons in the cerebral cortex (the most outer portion of the brain, where the nuclei of neurons are located). The first one occurred in an interval from around 4 to 3 million years ago, matching the emergence of the australopithecines, a group of hominins that includes the genus Australopithecus, a paraphyletic aggregate, since some of the species encompassed within this grouping are actually more closely related to the genus Homo than to each other (in that regard, we can still be considered Australopithecus). The second one occurred in an interval from 3 to 2 million years ago, coinciding with the rise of the first likely hominins to leave Africa: Homo erectus. The third duplication would only occur in a later interval, from about 1 million to 400 thousand years ago, a timespan that would see the rise of the most derived of hominins: descendants of Homo erectus such as ourselves (Homo sapiens) and neanderthals (Homo neanderthalensis).

Either way, Homo erectus would not only be likely the first one to venture beyond its birthplace, but also the first in several breakthroughs that would lay the groundwork for its future kin. Certainly, one of the most pivotal of these breakthroughs was the intentional and controlled use of fire. You may wonder about the need for these two adjectives, dear reader, but the fact is that many other animals use fire, such as dinosaurs, that, in the form of birds, may actively spread it to flush out terrified animals, which then become easy prey items. Our genus’ fire use may have started in quite a similar fashion. The seasonally dry savannahs of Africa, without a doubt, provided ample material for the spread of wildfires and, thus, great opportunities for hominins to gradually familiarize themselves with the phenomenon. Not only did these primates take advantage of the greater abundance of prey after fires, but they likely also noticed how certain foodstuffs, once burned, became more edible. However, especially during the wet season, such food items would disappear due to a lack of fires. This likely drove some of them to develop mechanisms in order to preserve fire, such as collecting and storing matter that could be used as fuel, like wood and even dried animal dung. All of these behaviors were quite sophisticated, for they demanded several thought processes behind them: observation, experimentation, and long-term thinking. Of course, all of these were only possible as a result of the previous cognitive development Homo erectus and its fellow relatives had already undertaken.

Decisively, however, the use of fire was not only a product of such cognitive abilities, but also a driver behind them. Not only did cooked foods allow for nutritionally richer meals that provided more energy to fuel the quite metabolically expensive, ever more complex brain, but the need to maintain fire and to stock up on fuel likely drove further social interactions, as few individuals could not accomplish all of these tasks alone, ushering in a primordial division of labor, a behavioral mechanism that allowed for greater efficiency in accomplishing tasks. Additionally, fire provided yet one more weapon to fend off against predators and, importantly, a tool to help extend the day, as now even the night could be illuminated. Apart from the obvious benefits this granted, such as additional foraging time and greater awareness of potential threats, it could have made available even more time for social activities.

These social activities were in full concert with another key developing trait: language, a feat also associated with the cerebral changes provided by the duplications of the SRGAP2 gene. While vocalizations are common among animals as a whole, in Homo erectus they likely began morphing into symbols, which are the association between a certain sound and a meaning. This provided these creatures the ability to extrapolate from the more basic referential vocalizations and start developing ways to more effectively plan out their activities, be it hunting, storing fuel, or building shelters. Essentially, the main difference is that, while before a sound was produced only in reference to something directly observed, then it began to convey information not directly observable, or better yet, to convey certain ideas, things which could only be done via symbols, which serve as an intermediate between the directly observable and what is being said. Symbols could also be combined, leading to phrases and even more complex information. Due to their arbitrariness (since they served as intermediates, subject to changes by the individuals utilizing them), symbols displayed significant differences between populations, especially in a species as diverse as Homo erectus, all features we can easily observe in the languages of the modern day.

All of these evolutionary and behavioral innovations were likely what granted significant success to Homo erectus, which, as cited a few paragraphs before, was likely the first hominin to make its way out of Africa, a movement also likely stimulated by the environmental changes afforded by the constant glacial-interglacial alternation of the ice age. Either way, they spread through Europe, the Middle East, and Asia, arriving all the way to what are now the Indonesian islands of Sumatra and Java, achieving a level of phenotypic diversity only rivaled by ourselves, Homo sapiens. From there, through a natural disaster, they likely were the ones to give rise to the Homo floresiensis we observe right now. These individuals we look at have no idea of their heritage, or that a whole other world of humans exists beyond this island. But the first of their kind to arrive here still spoke to their children and grandchildren of other humans beyond the beaches, but, alas, that was 1 million years ago, a time too long for us to truly grasp, even though we have been traveling through the past since the beginning of Earth’s history. Perhaps sadly, no more Homo erectus are still to be found: the last ones probably died out some 50 thousand years before this tale.

However, this is a bit of a deceptive statement, since, as said before, they left many descendants, including ourselves. As such, it is more appropriate to see it not as real extinction, but rather as change. Either way, what made those Homo erectus that did not transition into other species, such as ours or that of Homo floresiensis, extinct is unknown and rather perplexing, considering how adaptable these creatures were. It is likely it was a conjunction of factors, as with many other events we have witnessed along these tales. Possibly an amalgamation of the varying climate of the ice age (the last known Homo erectus, located in Java, possibly disappeared as a result of the shift from more open woodlands to rainforest), together with competition from their descendants (at least some groups of Homo erectus appear to have restricted themselves to collect nearby materials, while us, Homo sapiens, and other more derived humans gathered harder to access, but higher quality ones), and simple absorption into larger populations of those descendants, which, with even more highly developed cognitive skills, had more means to become more abundant and successful.

Here in Flores, though, these humans have lived in fairly undisturbed isolation. The extinction of Homo erectus in the mainland has meant that no more large humans adrift have appeared here for many thousands of years, but, even without these far-away additions, Homo floresiensis has managed to eke out an existence in this sometimes quite hostile island very well. Certainly, the most obvious of adaptations to insular life is their size, which was greatly reduced shortly after the arrival of their progenitors. Food opportunities are much scarcer here, not only due to the size of the landmass and the periodically dry times of year, but also due to the intense natural phenomena common in this part of the world, mentioned briefly before. As such, the descendants of the stranded Homo erectus that did not grow as much as the others had more success, as they needed to eat less to sustain themselves. Over thousands of years, they arrived in their current form, which has remained quite similar since then. Accompanying their decrease in size, their brain also shrank dramatically, but this does not mean they are any less intelligent than the hominins that gave rise to them, since the part of their brains associated with more sophisticated cognitive abilities is still well-developed, with they still practicing many of the same groundbreaking activities first seen in Homo erectus.

One of these we can easily observe, or, more appropriately, hear, that obviously being speech. While these five Homo floresiensis walk around the forest, they are constantly making remarks and, though it might seem to us just like grunts and gibberish, for them it makes perfect sense. It is not a dissimilar experience from hearing a foreign language we have no knowledge of, and, even though what they say is not as complex as all that we speak, it is hard to tell, so difficult it is to discern meaning. But one thing is clear: they gesticulate a lot while walking, frequently pointing to things and other times making elaborate movements with their hands. This is an indication that they still need to complement their simpler vocabulary with recurrent visual symbols, but, again, not too dissimilar from when we avidly use our hands or objects around us to explain difficult-to-grasp concepts. Curiously, they also have some difficulty, if not complete inability at all, to discern what other groups of Homo floresiensis say. Though Flores is not so big of an island, these hominins do not live all as one unit and, through the many, many years they have been here, a few contrasting dialects have developed.

Overall, it is of the uttermost strangeness seeing beings so close to ourselves, especially considering we are the last humans on the planet, plentiful, but lonely. Of course, we have already contemplated much stranger creatures and discussed bizarre lifecycles, but, even so, here we are, staring at some of our closest relatives and witnessing actions we normally consider unique to ourselves, things that make us think we are a special species, different from all the others. Special we indeed might be, but we are certainly not so different, only one of a myriad of humans.

Moving away from the shock and more philosophical thoughts, let us focus on the surrounding environment. It is a woodland, distinguished from a forest by the more open canopy, allowing light to filter through. For the baby Komodo dragons viewed earlier, this is great due to allowing plenty of basking spots on the branches. Unlike most other lizards nevertheless, these reptiles, being monitor lizards, sport higher metabolic rates than their relatives, maintaining higher body temperatures and being rather active animals, needing to eat more as a result. Apart from this more endothermic quality, they, also unusually, have a separated ventricle (lizards tend to have a heart with communication between the atria and the ventricles), allowing less mixing between poorly oxygenated and richly oxygenated blood and thus ensuring greater capacity for demanding activities, such as moving rapidly after prey.

Though the Homo floresiensis occasionally consume the dragon younglings, they generally do not, as the lizards, apart from being fast, can do quite a bit of damage by scratching and biting, especially because they release some venom during particularly long bites, a toxic cocktail that can cause weakness, dizziness, and exacerbate the pain from the bite. Not only this, but their teeth, mostly concealed by their large gums, are apt for tearing flesh, and so the results can indeed be quite nasty. Consequently, most of the time, the tiny hominins of this island, at least the ones of this group, eat giant rats, which provide plenty more meat and are common here as well as in neighboring islands. The largest of these is still extant, being the Flores giant rat (Papagomys armandvillei), reaching lengths of up to 75 centimeters. Another member of its genus can also be encountered here, Papagomys theodorverhoeveni, which, though not as big, is still ginormous for a rat, with roughly 60 centimeters from the snout to the tip of the tail. The reason for their increased size is probably fewer predators when compared to the mainland, following the opposite trend of the humans they share their habitat with. Even though the predators may be fewer, they, for the rats, are no less capable of predation, and looking for prey is what these humans are doing right now.

P. armandvillei live in burrows and are somewhat elusive mammals despite their large size, with this in large part due to the fact that they are nocturnal. With small ears, a robust body, and a fairly short, scaly tail when compared to that of other rats, it blends in well with the underbrush, especially due to the black coloration of its fuzzy yet rough coat, though it commonly climbs trees to access fruits, even managing to drill into coconuts using its ever-growing incisors (first mentioned here). With a diet consisting not only of fruit, but also of grasses, roots, tubers, and insects, this rodent is as much of an opportunistic eater as are its hunters. Like the smaller species P. theodorverhoeveni, it primarily dwells in more open habitats, but these have become more restricted in the last thousands of years, causing an increase in the number of medium-sized rats. Even so, it is an abundant creature, but producing small litters (only two to three young, unlike smaller forms, which generally give birth to a much higher number of babies) during the times of the wet monsoons, yet to arrive.

In regard to litters, and very much like other rats, the killing of babies is a very much real occurrence. For males, eliminating the offspring of a female leaves her available for reproduction once again, while for females, who need to compete for limited burrows in which to rear their vulnerable young, which are still poorly developed at birth, it is a way to drive off other females from desired nesting sites. However, unlike in other rat species where this is commonplace, the solitary nature of P. armandvillei means infanticide is not as frequent, since these rodents occupy larger territories that do not overlap as much.

Though the Flores giant rat is not venomous, as is the Komodo dragon, it still is a dangerous quarry. Its teeth are powerful and can pierce through meat much more easily than through coconuts. As a result, the ingenious primates have developed specific strategies to deal with these feisty creatures. Right now, they have located a burrow that likely belongs to one of the titanic rats, situated between two medium-sized rocks at the woodland’s edge. Considering the time of day, the rodent is likely in its hole. The band of five approaches the den of their target carefully. One of them, a male, is carrying a long but thick stick. It has several narrowed points along its extension, making clear what it is used for: a sort of bait. Slowly, he introduces a piece of the stick that is not yet chewed over into the dark space. As he proceeds, there is no contact, and it appears that there may be no one home, but soon enough, he touches something of a firm yet soft and somewhat fluffy consistency. This is it. He proceeds to aggravate the until then sleeping animal by repeatedly smacking it with the wooden tool, until they hear from inside an enraged squeal.

The man feels two paws closing around the stick and four teeth chiseling rapidly and furiously. He releases what we perceive as a grunt and, to his command, another one of his group’s members positions himself on the rocks surrounding the burrow’s entrance. The hunting companion is carrying a fairly large piece of chiseled stone containing two prominent, sharp edges. After the Homo floresiensis with the stick sees his hunting mate assume the correct spot, he rapidly withdraws his tool from the P. armandvillei’’s den, revealing a black and plump rat strongly gripping the piece of wood and rapidly destroying it. Before the rodent has time to react to the four bipedal monkeys in front of it, the man with the stone delivers a fatal blow as he rapidly descends the rock on top of the rat’s neck. Immediately, the prey releases the contents it was storing both in its bladder and its rectum, and a great amount of both as well. The hominins do not know it, but the danger this rodent poses has not ended with its death.

That is because, released in its urine, are considerable numbers of a bacterium known as Leptospira. It is a spirochaete, an ancient and monophyletic grouping of prokaryotes that has, as a key attribute, a spiral shape. The ones of the genus, apart from being elongate, thin, and corkscrew-like, are also bent in their extremities, leading them to distantly resemble a question mark. Inside their periplasmic space (for a better explanation, return to the first tale), spirochaetes have flagella, which, unlike in other bacterial cells, are not in contact with the environment (this grants them the advantage of not being hindered by more viscous surroundings), wrapping around their bodies and driving them in a rotating swimming motion that resembles a drill. Leptospira in particular have one pair of flagella, but the number varies from spirochaete to spirochaete. In rodents, these organisms (of the species Leptospira interrogans) exist without causing symptoms, inhabiting renal tubules, where part of the urine is formed and conducted through. From there, they are released into the environment, where they may survive for prolonged periods, though, without a host, death eventually ensues. However, these microbes have means of penetrating vertebrates, especially through breaks in the skin or via mucosal sites.

Once inside, they disseminate to various organs around the body, from the brain and the eyes all the way to the kidneys. In rodents, they get cleared from everywhere except the latter. In humans who become infected, rapid clearance (primarily through a combination of antibodies and immune-associated proteins naturally present in blood known as complement) takes place, except in the previously mentioned sites, but the only one where the bacteria are able to significantly proliferate is also in the kidneys. Unlike in rodents, there is disease in humans, possibly as a result of an inability of the human immune system to properly interact with a pathogen that has plagued its fellow mammals for likely far longer. For instance, rodent macrophages are capable of readily degrading the prokaryotes, while the ones of humans are frequently unable to do so, with the parasites managing to escape. Even so, in most cases, symptoms are mild and generally self-limited. But, in others, they may be quite severe, as renal failure ensues and dangerous waste products, such as urea, build up in the bloodstream, eventually leading to systemic dysfunction and death. Importantly, other organs might be affected, including the liver, which, functioning as the main metabolizing site in the body, is also essential for the maintenance of waste products. Its compromise leads to a characteristic yellowing of the skin and eyes known as jaundice, occurring as a result of the buildup of breakdown products of hemoglobin. Though the pathologic mechanisms by which L. interrogans acts are not very clear, it appears that, like in rickettsial diseases (explored during our first Cenozoic trip), damage to the endothelium is the main phenomenon behind the disease.

Many Homo floresiensis have fallen victim to Leptospira infections, especially during the rainy season, when the bacteria residing in the environment get carried off by the running water into rivers and streams that serve as drinking sources. A few also get contaminated by handling infected rats, a thing this one might possibly be. Fortunately for the hominins, the antibodies against this microbe persist essentially for life, meaning one who gets infected generally does not do so again, and this is thanks to the ability of some of the activated B lymphocytes, the producers of antibodies, to persist after the pathogen is eliminated. Consequently, mostly the young of these humans are affected, and this is such a remarkable pattern for many illnesses that they have noticed it, though the reason for such association will still take some 50 thousand years to be discovered.

From the woodland, the dwarf humans look to golden meadows that stretch as far as the eye can see, occasionally pinpointed by clusters of palms and by lonely trees. Grazing on the grasses is a herd of Stegodon florensis insularis, a subspecies that descended from an originally larger form known as Stegodon florensis florensis. These are, like Homo floresiensis, dwarfs, being miniature proboscideans only 1.3 meters tall at the shoulder, also a result of decreased food sources here on the island. Curiously, there existed another species of Stegodon here before the arrival of the larger subspecies that eventually evolved into the one we are observing now: Stegodon sondaari, which was even smaller, only 0.9 meters tall. Since their arrival here, these afrotherians, which are closely related to elephants (a grouping that includes the more well-known mammoths), have shifted to a diet mostly based on grasses, as we can currently verify. This transition likely was not too big of a problem, as these animals are very well adapted to consume even the toughest and most silica-rich monocots, for, unlike other mammals, their teeth are constantly replaced, with the ones most worn down giving way to new, erupting teeth that come from behind. Of course, the most visible of teeth, and which serve to grind no plant matter at all, are their tusks (modified incisors), which, even in this small subspecies, are still quite sizeable. However, the recent decrease in more open spaces and the advance of woodlands has made them move a bit, abandoning older territories now occupied by trees.

Unlike Homo floresiensis, which probably arrived on Flores as the result of several accidents, Stegodon, very much like other proboscideans, are quite competent swimmers, and this explains how they have gotten here not once, but twice, apart from also reaching other harder-to-access locations, even in times of receding seas, such as Japan. Intriguingly, like the genus Homo, the genus Stegodon is also very diverse. For example, the species S. zdanskyi, a native of China, reaches 3.87 meters in shoulder height, while one closer to here, the Javanese S. trigonocephalus, stands at around 2.5 meters high. Unlike Homo, though, which originated in Africa, Stegodon probably first evolved in the Tibetan plateau during the Miocene, later expanding to the rest of Asia and eventually even making its way to the African continent by about the same time hominins were appearing. But, like Homo too, Stegodon, and also like elephants in that regard, is highly social, as is already evidenced by the herd they form. And, like other proboscideans, these diverse mammals are matriarchal and live in groups controlled by an old female, while males lead a mostly solitary existence, occasionally uniting with their peers of the opposite sex to breed. During certain times of year, there is a considerable increase in testosterone levels among the loners, triggering a state known as musth, which is marked by extreme aggression. This drives males to rival other males for access to mates. Curiously, the length of this state increases with age, meaning older bulls stay aggressive for longer and more defensive of their breeding rights.

The hominins watch the fellow placentals with curiosity and a certain degree of awe, if we can even call it that. For them, as in many human cultures, proboscideans are targets of admiration and, in some instances, even of veneration. For the Homo floresiensis, though they occasionally hunt these beasts, they are seen as, despite the obvious physical differences, close kin of their own. Like hominins, these creatures are very intelligent and very social, displaying behaviors we so often associate with our kind that it is difficult to imagine them practiced by other animals. One such behavior is, amazingly, mourning. Not only do they occasionally visit the carcasses of long-dead companions, but mothers may even go on to bury their young, later avoiding the areas in which they were buried. It is hard to tell, if not impossible, what goes on inside their heads, but, once again, it shows how we are not so unique as we may believe at first. Partly due to these, burial acts and a connection even to those now gone, the Steogodon have a special place in the minds of Homo floresiensis, who also bury and miss their dead.

Despite this more tender side, as just cited with musth, these trunked synapsids can also be more than ruthless. The band of five humans is suddenly startled and jerks intensely once they hear a loud trumpet coming from a hill nearby. Soon, the owner of the trumpet makes itself visible: a young male Steogodon, shaking his head menacingly and moving his trunk with fierce movements, from side to side and up and down. An older male, currently accompanying the herd of females, notices his rival and imitates him. Both have a strange oily secretion oozing between their faces and ears: it is prevenient from a temporal gland, a modified type of apocrine sweat gland that becomes more active under certain conditions, such as during the increased testosterone levels of this state. Soon, there is no more sound, as the two attempt intimidation via low-frequency rumbles quickly transmitted by the ground. The male trying his luck does not back off and moves slowly in the direction of his rival. The humans stare intently while white-headed vultures (Trigonoceps), once constituting winged shadows circling in the sky, land on the ground and observe the dispute from a distance, already detecting that there might be carnage. The females and calves of the dominant bull look at the possible usurper with a mix of caution and curiosity, but, unlike in rodents, infanticide is not a common occurrence. Either way, the old bull is steady in his steps, and soon both are face to face. It almost seems like a staring contest until, after a few seconds, the older male again walks calmly in the direction of the pretender, who does not retreat and moves his head forward aggressively, almost to the point of his sharp tusks making contact with the leathery hide of his opponent. This is a bit too much for the old bull to tolerate, which charges head-on, slamming with full force on the cranium of his adversary. The young Stegodon was surprised, but managed to bear the brunt of the attack, resisting fiercely against the push of the old bull.

After about one minute, the two proboscideans disentangle themselves. They are still silent to our ears, but sending several sounds too low-frequency for us to hear, each one coming with a response, an ever-escalating exchange of rumbles. The bull moves slowly in the direction of the younger male one more time, but, once more, he does not yield and, this time, takes the initiative, slamming at the significantly older adversary and trying to stab him with his ginormous incisors. The old male makes swift maneuvers and avoids the potentially fatal tusks, trying to shift the scales to his favor. Fortunately for him, he is not only more experienced but also slightly heavier, and a decisive push is all he needs to end this once and for all. With a turn of his head, he makes the young Stegodon lose his balance and fall to the ground, causing a great cloud of dust to emanate from between the trampled grasses. In most cases, fighting would not even get to this point, and, in most other cases, it would end here, but not this time. In an instant, the bull drives with noticeable fury his two tusks into the belly of the fallen enemy, tinging them with blood and making the younger male trumpet in pain. The Homo floresiensis even cover their ears, but continue watching. Their reverence for Stegodon is also due to its raw power: they very much know the damage such beasts are capable of, and now we do too.

The bull looks upon his agonizing rival and returns to the herd, which, taking one last gaze at the disgraced male, carries on, looking to graze elsewhere. With the departure of the old male, the vultures hurriedly move to the dying beast, walking with their necks down and bobbing their bodies in a movement that can be considered almost comical. With pale heads adorned by a fluffy white piece and colored in quite pleasing shades of pink and blue, these count with a striking dark brown and white coat, apart from very noticeable pink feet and an also vibrantly colored orange beak. Extant only in Africa, these are reasonably large vultures, with a wingspan of up to 2.3 meters, meaning they are truly gigantic for the Homo floresiensis and both often compete for resources, as, though a scavenger, this bird is also a hunter, with a great part of its diet being composed of small prey.

It is a rather solitary vulture and forms monogamous pairs that are highly territorial, nesting in trees. Some within this band of small humans have already had the displeasure of wandering into the territory of a couple of these animals when they were taking care of their chicks and, though they came out alive, they were left with severe scratches and lacerations as the theropods harassed them with their beaks and talons. Dwelling into avian classification, Trigonoceps are part of a group known as the Old World vultures, which, together with eagles, hawks, as well as several other birds, comprise the order Accipitriformes, which constitutes a sister group to the Cathartiformes, represented by the New World vultures. Splitting earlier from the common ancestor that led to these two orders are the Strigiformes, composed of the iconic owls, some representatives of which will be seen later.

Soon, another reptile appears to take its share of the carcass: a fully grown, 3-meter-long Komodo dragon, with a dull brownish-gray coloration when compared to the relatively colorful younglings. Walking undulating side to side, it reaches the almost dead proboscidean fast, and the few vultures distance themselves from it as they peck at the beast, tearing small pieces of flesh while it is still alive. Perhaps a scavenger even more than these coelurosaurs, Varanus komodensis has around half of its diet composed of carrion. As it finally reaches the soon-to-be-deceased mammal, it rips into the hide of its target, jerking its head violently while its hidden teeth, especially adapted to slash and tear off meat, cleanly cut everything between its jaws. In an instant, it has already grabbed a sizeable piece of meat, gobbling it down eagerly, a feat made easier by its relatively flexible skull. The hominins look at the reptilian creature with a mixture of horror and disgust. Though it is also a demonstration of the raw power of this island’s fauna, it serves almost as a polar opposite for the Steogodon: while they show some care for their dead, it is a consumer of them. Additionally, the keen sense of smell of Komodo dragons, aided by their always flicking tongue and their powerful paws adorned with sizeable claws, enables them to easily locate and then dig out the graves made by the Homo floresiensis, which, to say the least, grants them quite a negative reputation.

Even before the Komodo dragon, other much tinier scavengers arrived, though they are almost always, to some degree, present. They are flies, insects that, to this day, constitute quite a nuisance and, more specifically, brachyceran flies, characterized by their more robust body shape when compared to the way more gracile mosquitoes. However, despite their ample and overbearing presence currently and already by the time of this tale, the types of brachycerans (called blow and flesh flies, the first being characterized by a metallic coloration) swarming the afrotherian actually are fairly recent in evolutionary terms, dating back to the Neogene, a couple of million years before our voyage to Patagonia (the grand majority of Brachycera as a whole evolved after the Cretaceous-Paleogene extinction, in conjunction not only with the rise of mammals, but also of the higher temperatures, and the ever more abundant angiosperms). Their development was likely associated with the spread of grasslands mentioned then and the subsequent rise of grazing animals, which they accompanied, using their dung and carcasses as breeding grounds. With time, some of these holometabolous insects started using live creatures as a way to nourish their young, giving rise to several independently evolved parasites, such as the infamous screwworms. These arthropods are not so different from their relatives that use excrements and corpses, being just more precocious, and intermediate stages like the one where the male Stegodon finds himself were likely the way these flies started this mode of life.

Ample evidence of this merely precocial nature is given by the destructive effect of their maggots, which, with chitinized fangs, are true flesh-eating bugs, consuming anything in their path while they explore their host. Sometimes, the parasite burden is so great that the parasitized animals may even die. If they do so, it is not much of a problem, as the immature flies, cylindrical, segmented, and even bristled (somewhat resembling annelids), generally continue eating until they reach a certain size, after which they leave their flesh abodes, transforming into pupa, becoming a hardened, non-feeding form that is undergoing a radical process of reorganization internally, transforming from a vermiform creature into one with six legs, two wings, compound eyes, and three well-demarcated body segments. After their metamorphosis is complete, they emerge as flying adults. These soon encounter themselves to reproduce and consume a wide variety of food sources, be it nectar or the substrate on which their offspring will develop, especially needed by females, which require a protein source to fuel egg development (much like their relatives, mosquitoes). After mating, those eggs are laid and, from these, the larvae emerge, ready to begin the cycle anew. Curiously, the flesh flies even exhibit a type of ovoviviparity, with them retaining their eggs for extended periods in a uterus-like pouch, releasing them only when they are ready to hatch.

These dipterans, especially blowflies, may even display a symbiotic association with certain members of the phylum Bacillota, these being Clostridium bacteria, which constitute a genus of prokaryotes that is generally obligately anaerobic, being unable to survive under oxygen and thus transitioning into an extremely resistant state through sporulation, a process restricted to certain types of bacteria in which they become dormant, potentially for many years. In the case of this genus, sporulated cells often appear similar to tennis rackets or drumsticks, as the spherical spore may be located on the extremity of the rod-shaped bacterial cell. Either way, Clostridium are very widespread, ranging from aquatic habitats all the way to the microbiota of terrestrial animals, being quite abundant in the soil. Some of the most infamous species of Clostridium are those known to promote severe human disease, such as Clostridium tetani and Clostridium botulinum, the causers of tetanus and botulism, respectively. Both of these conditions are remarkable in causing paralysis through roughly opposite mechanisms: tetanospasmin, the toxin produced by C. tetani, acts on inhibitory neurons of the central nervous system, cleaving neuronal proteins associated with neurotransmitter release and leading to uncontrolled muscle contraction, called spastic paralysis, while botulinum toxin, produced by C. botulinum, also cleaves neuronal proteins associated with neurotransmitter release, but it acts on peripheral motor neurons and affects acetylcholine, which is responsible for kickstarting muscle contraction, leading to flaccid paralysis.

Both are lethal, for the two can lead to respiratory failure by compromising the diaphragm and other respiratory muscles. However, the way of acquisition varies. Tetanospasmin must be produced by proliferating C. tetani within the host, with these bacteria usually finding their way inside through more serious breaches, which need to be sufficient to compromise blood supply and thus ensure an anoxic environment. Botulinum toxin, though, usually affects animals by being pre-formed in a suitable medium, being capable of crossing the intestinal barrier into the body (this is why C. tetani can exist within microbiotas without causing disease). This is all well and good, but why would these prokaryotes evolve such incredibly specific and potent toxins to achieve paralysis?

Well, sometimes, there is not a why and, should these toxins neither grant any benefits nor harmful costs, they could have simply stayed there, especially if they originated from a previous viral infection, which seems plausible, considering the presence of similar proteins in other, more distantly related bacteria (though the more basal of these proteins appear to exert other functions, with these potentially being ancestral and only later evolving into the paralytic roles of today). But, especially in the case of C. botulinum, these toxins might have acquired importance in their ecology, and this is revealed by their association with blowflies. These insects serve as important carriers of C. botulinum spores, and they, when consumed by a bird, for instance, can seed these bacteria within the theropod’s gut, with them germinating and eventually killing their host. However, before the host is killed, it becomes paralyzed, and this is the perfect opportunity for the blow and flesh flies that are precocious carcass layers, offering them a host that is basically equivalent to the moribund Stegodon, one still free of competing scavengers and decomposers.

However, these are not the only parasitic flies that originated later in the Cenozoic. Some are quite more adapted for inhabiting their hosts and exhibit a high degree of host-specificity, apart from several other remarkable adaptations indicating a completely parasitic lifestyle. These are the bot flies, fairly close relatives of the blow and flesh flies, but with key differences. First of all, their adult stage is remarkably fuzzy and more robust, importantly with non-functional feeding apparatuses, unlike the blow and flesh flies, which have spongy mouthparts for sucking. Indeed, the adults of these flies do not eat and only reproduce, living briefly, to a maximum of usually 2 weeks, depending on the species. After mating, females lay the eggs on multiple hosts, a behavior that ensures there are not too many larvae on the same animal, helping the survival of both, since the young of bot flies die together with the one they parasitize. Overall, though, they are similar to those of the previously mentioned flies, but usually larger. Despite their increased size, these maggots are actually less harmful, staying restricted to more specific bodily sites and even secreting substances that, by compromising bacterial growth, prevent wound infections. In the case of the Stegodon, they are targeted by a botfly with a very peculiar life cycle and one that still exists today, affecting both African (Loxodonta) and Asian (Elephas maximus) elephants.

This dipteran is part of the genus Cobboldia, with adults sporting a rather pretty coloration marked by orange heads and black bodies tinged with one white spot on each side. These botflies lay their eggs on the base of the tusks and, from there, the hatched larvae find their way into the stomach of the proboscideans, where they, with their tails turned to the gastric cavity (the openings of the tracheal system of maggots are located at the tip of their tails), “graze” on the mucosa of the organ with their chitin hooks, growing bigger and fatter. Eventually, once they reach a certain size, they go back the way they came, being spit out by the placentals into the environment. There, they pupate and emerge as the brightly colored adults, ready to mate and ensure the continuation of the next generation of Cobboldia. Humans are not free of bot fly parasitism either, and the Homo floresiensis are reasonably familiar with the small holes in their skin from which the tails of the larvae arise. They even treat their condition by tightly applying a leaf over the maggots, depriving them of air and making them often wiggle out in desperation.

Well, now returning to the larger scavengers, Homo floresiensis have one more reason to loathe their ginormous reptilian neighbors. Unlike the African and continental Asian carnivores their ancestors co-evolved with, the Komodo dragons are far from picky eaters and consume the majority of carcasses, up to the bone, leaving far less for the tiny humans to scavenge on. However, they still have a certain degree of luck, for these monitor lizards actually originated in Australia, where a larger relative of theirs roams: Megalania (Varanus priscus), reaching sizes of more than 5.5 meters in length. But, of course, they do not know of these even bigger monitor lizards just a little down south, and, due to their small size, the dragons of Flores already serve as their very own Megalania all too well. After witnessing the whole brutal spectacle, the group once again retreats deeper into the woodland, carrying away the rat killed before. For these five, witnessing death is nothing new, and, just as for us, it is a phenomenon that carries great significance, explaining why they even bury those who have passed away in the first place.

But they have recently had a near-death experience they would rather forget. Like many other hominins, including our own species, Homo floresiensis engage in cannibalism for a multitude of reasons. Though in a few cases these are the result of ritualistic practices, in most they occur due to what is termed gastronomical cannibalism, which is the act of eating another of your own species purely for nutritional means. Just a few days ago, they were part of a larger group, about twenty strong or so. However, during a previous night, their temporary settlement, established in a reclusive and fairly privileged location, was invaded by a larger group of starving tiny humans. For all they know, only they five were able to escape to massacre, as their companions, mostly asleep, barely had time to react before being butchered by sharp and heavy stones. Since that tragic day, they have never remained somewhere for long, traumatized and fearful of any humanoid outline that may seem to materialize in the corner of their vision. One of the females amidst their group lost her mate that day, and she has changed more than the other ones, feeling like her entire life has been hollowed, scooped of the substance it once had. It is hard for her to express it to her peers, but, even today, we have great difficulty explaining similar emotions as well.

With the P. armandvillei in hand, they walk for a few meters until finding a clearing: a good place to set up camp for the day, one where they can watch all their sides and prepare the sizeable rodent for consumption. The two males and one female start removing the animal’s pelt, using the stone they used to kill it as well as two other rocks, which, flatter, serve more like blades, apt at slashing its fuzzy hide. The grieving female goes out into the woods together with another woman, who, having learned from her parents, is the group’s cook, knowing what is edible and how to combine certain foods to make more tasteful meals. In this case, she is on the lookout for herbs. Since giant rat was a common dish among their group, the woman knows what to look for, and that is basil (Ocimum basilicum). Despite its great presence in the Mediterranean culinary tradition of our species, this eudicot angiosperm is actually native to Asia and Australasia, being introduced to Europe only thousands of years after this tale. It has a powerful aroma that is difficult to describe, but it possesses a characteristic herbal quality nevertheless.

With soft, triangular leaves that range from a vibrant green to deep shades of purple, this aromatic plant is part of the family Lamiaceae, which also counts with plenty of other rather fragrant species, such as rosemary (Rosmarinus officinalis), oregano (Origanum vulgare), mint (Mentha officinalis), as well as many others. All of these share as the source of their hallmark smells substances known as essential oils, which in the plants serve several important functions, like acting as antimicrobials and as antioxidants, neutralizing dangerous oxygen species, often a product of the photosynthetic process. Some of these beneficial effects are translated into those who consume them, and that might be part of the reason they have become ingrained in the cuisine of these almost hairless monkeys, for, apart from their pleasant taste, they confer positive repercussions that perhaps gave the hominins that consumed them greater success along their almost 1 million of years on this island.

It is right in the middle of the peaceful activity of basil collecting that the two women hear a sudden boom. They cower for an instant but then rapidly return to their previous dispositions. It was only thunder, a phenomenon that, though they are accustomed to, is rare during this time of year. Soon, the air is filled with misty smoke and an unmistakable burnt smell, signaling a fire nearby. Quickly abandoning the cook, the other female runs in the direction of the acrid odor and of the gray smoke, collecting any dry sticks she can find along her way. Soon, she arrives at the source: what was once a golden plain is now burning bright with orange and darker yellows as the ground beneath becomes a mixture of jet black and silvery ashes. Calmly and carefully, she gets close to the dancing flames and touches them with one of the sticks. After a few seconds, it ignites and she puts another amidst the fire. Holding two fiery sticks with her hands and with plenty of other wooden pieces underneath her arms, she returns to her foraging mate, and both go back to the clearing. There, the others had already managed to almost completely de-skin their prey, and, with the pieces of wood placed on the clearing floor, the fire-bearing female throws one of the fiery sticks into the pile. The other one will be reserved for other potential uses, as these woods are far from safe.

Soon, the night finally sets in and the Homo floresiensis continue preparing their meal, now only waiting for the cook to finish making a basil paste to pass over the rat before it is roasted over the fire. A noise of large things breaking apart twigs deep in the clearing makes them turn their heads rapidly. Fortunately, it is only a herd of Stegodon, a distinct one from that they saw earlier, as is made evident by the presence of only two calves, content playing with one another, running, smashing their heads, gnawing on each other’s tails, and knotting their trunks. It is a calm scene, and the hominins find some joy watching the younglings enjoy life in such a carefree manner, for, unfortunately, it is something that in many cases does not last for very long.

Almost as if on cue, another creature emerges into the clearing: an adult Komodo dragon. The reptile takes a look at the proboscideans and then at the humans, splaying its legs while it does, constantly flicking its tongue. Soon, it abandons its resting position, walking resolutely in the direction of the primates’ fire, the full extent of its powerful musculature showing as it alternates side to side. The two men, one carrying a fiery stick and the other the rock he used earlier to kill the Flores giant rat, stand up to intercept the creature. As they approach, it opens its mouth wide and releases a loud hiss. The two humans retreat a bit, but ultimately stand their ground, shouting and gesticulating furiously, almost burning the tetrapod’s scaly hide. The women at the fire are not so worried, for these encounters are relatively common. Despite the great danger of the enormous lizards, they rarely attack in situations where they are at a disadvantage, being rather cautious creatures despite their fierce aspect. This one will likely soon go away, for the risk of going after the very good meal of a whole P. armandvillei is too high, even for the possible reward.

Unfortunately for the hominins, more than just one V. komodensis wishes to consume the product of their day-long effort. While macerating the basil leaves and stems with two stones, the cook hears twigs snapping behind her and, when she looks, two sinister specters, 1.8 meters tall, can be seen. With long, sharp beaks and very slender legs, these are two Leptopilos robustus, a species of adjutant stork, a genus that, still extant, extends from Africa all the way to these far reaches of Asia. Like the giant rats, the Stegodon, and even the hominins, it is mainly a dweller of more open habitats, the expansion of which probably allowed for its migration out of Africa in the first place. As mainly a scavenger, this bird takes advantage of ascending hot air to gain high altitudes without much flapping, transversing great distances while on its long and broad wings in search of food opportunities.

Of course, open environments are more favorable for this lifestyle, since locating carcasses is made much easier. Due to its large size, it is able to bully its competitors, such as the white-headed vultures and the Komodo dragons, threatening to deliver heavy pecks or even kicks. Despite this, they are far from invulnerable and, in a few cases, the large reptiles of this island have claimed some of them as their victims, especially after blows that, too slow, ended up with their feet inside the mouths of the terrible lizards. Even so, their large size is advantageous for other reasons apart from intimidation, with them being able to consume extremely large morsels of food, to the point of sometimes swallowing the vertebrae of dead proboscideans whole. However, these are not only scavengers, and the dry times of year offer them even more foodstuffs, as they wade into drying ponds, where aquatic creatures become ever more concentrated. There, they patiently await with their beaks open until an unlucky prey item crosses between them and gets captured.

Unlike the Trigonoceps with which the storks share their habitat, they are way more social creatures, nesting in colonies at the top of trees, with the increased heights facilitating their take off. They are monogamous as well, and part of courtship involves the creation of the nest, as the male gifts the female with sticks, which constitute the building material. Should the male’s initial advances bear fruit, then they proceed to hold their beaks close, a gesture of affection that eventually leads to the laying of eggs and the birth of ungainly, but extremely fluffy chicks. These two, analyzing their chances of stealing the deskinned rat of the hominins, are a couple that has already laid eggs, leaving them temporarily to look for food, a bit of negligence they can spare due to their colonial nesting habits. Despite their size and powerful beak, they are rather gracile creatures that can be somewhat easily injured and so they are patient, preferring to avoid conflict with the hominins.

Whilst these large birds are largely silent, baby-like as well as gurgling cries emanating in great numbers from the canopy come from much smaller theropods, from Flores crows (Corvus florensis), counting with a completely black plumage and slightly curved beaks. These are part of the Corvidae family and the order Passeriformes. As corvids, they are omnivorous creatures and quite generalist in their diet, but also monogamous organisms that establish pair bonds for the whole of their lives. Not only this, but corvids are widely recognized for their great intelligence, which is primate-like in several regards, with them making tools, recognizing dangers, and transmitting that information to other corvids, apart from many other exceptional abilities. Perhaps part of the reason for their more developed cognitive skills lies in the social life of many of these birds, which can be quite exuberant, full of intricate dominance hierarchies and bonds other than the reproductive ones previously mentioned. The point is that, in these avian societies, these birds need to have a good grasp of the social relationships between the various members in order to act in the best way possible, either to support one individual, for example, or to partake in attacking it. Not only this, but even less socially inclined corvids need to be aware of others of their kind, especially those that engage in the storage of food items, for they require not only to remember their own storage areas, but also where the ones of others are located, especially so that they can steal should they need to. In this sense, the birds also should be attentive to their kin, which, though a possible target to steal from, may also steal from them, so they need to be careful when selecting where to hide their edibles.

In regard to danger recognition and transmission by these theropods, even the Homo floresiensis are aware of this. They have observed that, should an individual harm one crow, they may be mobbed by the whole group in the future. Such a phenomenon is made possible by the fact these creatures remember faces and, when seeing that face again, they signal to their companions the danger that individual poses, triggering the collective attack or simply behaviors of avoidance. These informations can even be transmitted between generations, as young corvids spend some time with their parents (or potentially even with additional helpers, subordinate to the breeding pair) before flying off on their own and, even after that event of separation, usually form murders with other adolescents. Not only do these creatures spread details about possible dangers, but also how to fabricate and use certain tools, with inexperienced birds learning from those that are already familiar with their instruments. The Flores crows, for example, dwell through the forest in reasonably small murders, with their essential unit based on breeding pairs, as with many other corvids (though not all members of the group are necessarily paired). Some have learned, from observing others, to put seeds too hard to eat on the path of Stegodon, using the much heavier vertebrates to crack open the nuts for them.

Like with the Stegodon, the tiny hominins of Flores, at least the ones we have followed, hold these crafty creatures in fairly high regard. Not only do they recognize the many similar traits between themselves, but, most importantly, they value the importance that these dinosaurs also give to their dead. As with other corvids, these crows also engage in funeral-like practices, where, should they spot a dead member of their species, they send out various calls to signal others. There, they congregate and sing around the dead individual, sometimes nipping its feathers, but overall avoiding touching it. While this set of behaviors is potentially involved with grieving and distress, especially if the one to be found dead is a member of the bird’s social group, it is also a time of learning, as it functions to alert those alive that the area where their kin was found dead is a potentially dangerous one and that should perhaps be avoided.

Among the branches of a tree opposite to that of the crows lie more passeriforms, being, actually, two chicks of the songbird Heleia wallacei and their two parents, preening each other in areas they on their own cannot access, a practice that helps reinforce their bonds. They are quite typical songbirds, small, with a fairly plump body and sharp, pointy beak, apart from a vibrant coloration, with a gray belly and yellowish-orange face and tail, apart from more olive-colored wings. Their song is a joyful tune, an upbeat warbling that is quite pleasing to the ears. These are part of the white eye family, a group of theropods that extends from Africa, through Asia, all the way to Oceania, named due to the white rim of skin often found around the eyes of many of its members. Though currently we observe only these four, this family of birds is characterized by being quite gregarious, commonly wandering in flocks that, during the breeding season, may become incredibly large. They even form flocks with white eyes of different species and, in some cases, with birds that are not white eyes at all, usually being “leaders”, determining the directions the flocks take.

As the crows, these tiny dinosaurs are omnivorous, though the majority of their diet consists of insects. Even so, they still are avid consumers of fruits and nectar, the latter of which they access using their brush-like tongues, apt for extracting the sugary liquid. Also like the crows and as the great majority of birds, as a matter of fact, they are monogamous and, though their pair bonds do not necessarily last for the whole of their lives, they can endure for many years. Apart from this, the white eyes are very attentive and careful parents, never leaving the nest completely unattended during the early days of their offspring, with the parents taking turns while one watches the chicks. The nest is deep and cup-like, formed from plant material collected by the adults.

The tree they have formed their nest on also deserves a mention, for it is one of the few Eucalyptus species found beyond Australia: Eucalyptus urophylla. In the Australian mainland, these plants are dominant in a variety of habitats, and here in Flores, similar situations can also be observed. This species, for instance, which can grow up to 55 meters in height, is widely distributed around this and neighboring islands, growing especially in more humid and upland locations, actually being the Eucalyptus species with the highest altitude range. With a somewhat thin and spindly trunk adorned by branches containing leaves that taper into sharp ends, it shares a few attributes with its relatives, traits that help justify their abundance and distribution. The first of these is the plasticity of these eudicots, which can assume a wide variety of shapes depending on where they have established, allowing them to adapt to more unfavorable areas, places in which they do not attain their maximum sizes, sometimes being more akin to shrubs. The second of these is their bark, which protects dormant buds distributed across their trunk from wildfires, allowing new branches to sprout even if the previous ones were burnt to a crisp. The third trait is the presence of swellings at the base of their trunks, which, called lignotubers, are often concealed under substrate, concentrating buds and nutrient reserves that can prove pivotal to revitalize the tree even if the trunk above ground is destroyed.

Elsewhere, one can see two massive pairs of eyes, one a little closer to the clearing and another one deeper into the woodland. These are two owls, more specifically Scops owls, comprising the genus Otus. Like other owls, representatives of the class Strigiformes (mentioned earlier), these are predatory and carnivorous avians, with the great majority of their kin, including these ones, being nocturnal. As a result, they have several key adaptations that allow them to locate and catch prey even in the darkest of habitats (considering these still have some degree of light present). Most noticeable of all certainly are their eyes, which are incredibly large and forward-facing, giving them a high degree of depth perception. Not only are the eyes large in circumference, but they are tubular as well, extending deep into their skulls. This great size hinders the motor ability of such visual organs, but the owls are able to compensate for this by having very flexible necks, allowing them to turn their heads surprisingly backwards and thus get a good hold of their surroundings. Due to their times of activity, the retina of these reptiles is enriched with rods, the photoreceptor cells most sensitive to light, but only with one rhodopsin, thus transmitting only one color to be perceived (as explained in more detail previously). This means that they have greatly reduced color vision, contrasting with other birds, but in line with most mammals, which likely lost theirs as a result of the nocturnal habits of their ancestors, as also explained in the tale linked just before.

Apart from acute nocturnal vision, these creatures also have great hearing perception. This is potentialized by the asymmetrical placement of the ear openings in many species, with one ear pointing downwards and another upwards. This helps them distinguish the height of the sound. To further help pinpoint the location of anything they hear, their wide faces help to identify the sound horizontally. With these “coordinates”, the owls are able to strike with much greater accuracy. Apart from this, their wide faces may often sport facial disks, structures that can be contracted or expanded through their facial muscles, helping them tune in to hear the best they can, depending on the situation. Of course, these birds also count with other features shared with predatory avians as a whole, such as strong talons and a sharp, curved beak. Regarding their talons, they also have another curious adaptation: one of their toes, normally positioned back in a zygodactyl arrangement, can actually rotate forward, helping to restrain prey that may be more difficult to immobilize.

The owls that we observe here are fairly small, and though they count with these general adaptations, are predators of also smaller prey, usually capturing insects while on the wing, though occasionally the tiniest rodents of this island are targeted too. The one closest to the fire is a Flores Scops owl (Otus alfredi), marked by its fairly small ear tufts and light brown coloration mottled with whites and grays. With a length of about 20 centimeters, it usually nests in tree cavities and is only now getting ready to go out and hunt, observing the humans and their commotion below with some degree of curiosity. It is a fairly rare animal, with its vibrant yellow eyes an infrequent sight amongst the trees. Perched a bit behind it is the Moluccan Scops owl (Otus magicus), being larger by only a few centimeters and marked by its more prominent ear tufts as well as darker, more cryptic coloration, composed of a mosaic of grays and browns with darker stripes in between. Unlike its rarer relative, it is quite a bit more vocal, filling the nights with frog-like croaks, which are sung in a duet by pairs in courtship.

Below, and even deeper in the woodland, a dispute ensues, unnoticed by those that occupy the clearing. A reticulated python (Malayopython reticulatus), just calmly slithering across the underbrush, has found itself mobbed by two very protective orange-footed scrubfowl (Megapodius reinwardt). These are members of Galliformes and part of the family Megapodiidae, which has a hallmark trait the following behavior: instead of building nests, these fairly large, ground-dwelling birds construct extremely large mounds in which they bury their eggs, kept warm by the decomposition of organic matter with which the mounds are built (though some species use soil that is kept warm by heat emanating from the Earth’s interior). Monogamous, they build these mounds together and defend them fiercely from any perceived threat, unleashing loud calls that somewhat resemble those of peafowl (Pavo), another galliform. This snake has been erroneously identified as a threat and now it hisses, opening its mouth wide, while extremely large, orange feet with dangerous claws dance around it, a few centimeters away from potentially causing painful injuries.

After a few tense instants, the python manages to slither away unharmed, as, through a combination of hisses and attempted bites, the omnivorous saurischians managed to give it a wide enough berth to escape. In other circumstances, this extremely large reptile, easily reaching more than 4 meters in length, would indeed be preying upon these birds, but it has already eaten and can pass quite a long time without doing so. This individual is on the lookout for a body of water, areas where these vertebrates prefer spending most of their time, considering the increased difficulty of moving around with such massive bodies. This difficulty translates in their form of motion: instead of the serpentine movement we commonly associate with these animals, made possible by simultaneous contraction and relaxation of different muscles, the pythons move in a more caterpillar-like fashion, contracting and then relaxing. Not only can they move with much greater ease in aquatic environments, but they can also hunt more adequately, waiting in the water for as long as necessary before a suitable target comes around.

If the conditions are right, it will pounce, being able of biting into large creatures thanks to its flexible skull, capable of distending significantly. At the same time, it also coils itself around its victim, restraining and then asphyxiating it with the help of its powerful muscles. With the poor prey item dead, it will have plenty of time to slowly consume it, essentially lacking any predators. The most bothersome creatures to this squamate are the Homo floresiensis, which will throw stones and pointed sticks at it, potentially fatally. Even despite these tools, it is rather frequent for the tiny hominins to fall victim to this snake, especially when they are transversing wetter or more heavily forested areas alone. Indeed, this island is so full of dangers it is rather surprising how such small humans managed not only to persist, but thrive.

Speaking about caterpillars, an adult one can be seen resting on the trunk of a tree quite close to the Homo floresiensis campfire. It is an Attacus inopinatus, a species of very large moth (thus part of the order Lepidoptera), reaching 15 centimeters in wingspan and displaying a striking rusty coloration with white and darker markings. This here is a member of the family Saturniidae, which comprises other giant moths, all with a very velvety, fuzzy aspect. They start their lives as voracious caterpillars, which feed specifically on a type of plant, using their well-developed mandibles to crop up leaves and other vegetal organs, undergoing several molts until they are ready to pupate, with them forming a silk cocoon around themselves, inside which they undergo metamorphosis into their adult, winged forms.

Like the bot flies, these most mature stages do not feed and actually lack functional digestive systems, depending entirely on their energy stores they acquired as larvae. Their only desire is to mate, and they must do so quickly, with males having larger feathery antennae they use to locate females. These appendages are bristled as to increase their surface area, allowing the insects to “sniff” out pheromones, even if they are in low concentrations. This is also useful for females, helping them select the specific plants onto which they can then lay their eggs. Apart from sensing odorous stimuli, these structures are also essential for flight stabilization, detecting changes in the position of the moth’s body, and changes in the antennae themselves. All of these provide important input for the insect’s nervous system, allowing it to adapt to changes in wind, for example.

Below the moth, lie two rather discontented little lizards: two male Tokay gecko (Gekko gecko), barking (a sound that is supposed to resemble “tokay”, explaining their name) and hissing at each other, too occupied with one another to bother the insect above, which, in other circumstances, they might try to catch. Territorial, these geckoes, around 35 centimeters in length, are solitary insectivores, only coming together to mate. As such, this encounter here is more than unwanted, and they will only depart when one finally submits to leaving this area, going on the lookout for a territory of his own. As they hiss and croak at one another, bites are exchanged, though these have so far not made contact, being restricted to pure intimidation. Every time one tries to gain on the other, perhaps moving to deliver a nibble to a more vulnerable area, the rival repositions himself, so that they are always facing each other head-on. It is hard to tell how long this standoff will last, but should the fighting turn more serious or a predator disrupt their dispute (such as a young Komodo dragon), they can always release their tails, a behavior known as autotomy, which, observed before, is not ideal, but can be life-saving nevertheless. This process occurs thanks to a boneless fracture plane that exists in the caudal vertebrae, with little bleeding due to specialized muscles that pinch off the arteries and veins. With time, even a stub regrows, but the new tail is not as flexible as the first, since it lacks vertebrae, instead being composed of a cartilaginous rod.

Fortunately for these critters, most of the time, they do not need to sacrifice their original tails, especially seeing as they are not only masters of disguise, but can also reach very hard-to-access spaces. Regarding their first ability, Tokay geckos, with a base coloration of bluish-gray with red/orange spots, can change the tone of their skin, very much like the Platypterygius could, as we witnessed then. This allows them to better blend in with their surroundings and, aiding in this ability to camouflage, they have expandable skin folds running along their sides, which, once increased in size, conceal the shadow they make on the surface they are resting on, granting them even more concealment. About the second ability, it is possible thanks to the unique architecture of the underside of gecko feet, which are covered in great numbers by tiny plates, which then go on to branch into even smaller, microscopic structures that resemble hairs. These create a very large surface area, sufficiently big to allow Van der Waals forces to exert a noticeable effect: these forces exist between any molecule, regardless of its charge, and only arise at very small distances, sufficient to the point of causing a reorganization of charges within molecules, one that may lead to attraction between positive (due to protons, located in the atom’s nucleus) and negative (due to electrons, located around the nucleus) charges. Due to these properties, geckoes are equally adhesive on all surfaces and can effortlessly climb even the steepest slopes, a feat that is obviously very useful for escaping predators.

Shifting to arthropods once again, we see the intricate web of a rather curious spider. It has a large abdomen, covered in spikes, and with a harsh contrast between bright yellow and dark brown stripes. These traits denounce it as Gasteracantha taeniata, a species of spiny orb weaver spider, a genus of spiders characterized by extreme sexual dimorphism, with females being like this, from 0.5 to 0.9 centimeters in width, and males much smaller, lacking the abdominal spikes, which are used for defensive purposes, and being puny things, just at 0.2 to 0.3 centimeters. Only the females build these elaborate webs, releasing silk from organs called spinnerets, which, connected to internal silk glands, are located far back on their abdomen. These structures, called orb webs, are used to capture their prey items, mostly flying insects that accidentally fly into the trap. These traps are true feats of biological engineering, and, curiously, if starving, spiders may even eat their webs, but if under stress from hunger, they may still spin silk and, instead of spinning incomplete webs, they just make smaller ones, showcasing their ability not only to build, but also to assess how much building material they have.

Once the insects become entangled among the strands, the arachnid approaches and paralyzes them with its venom. In the case of this individual right here, a brachyceran fly has recently been caught. Being smaller than its indirect catcher, the C. taeniata will transport it to the center of the web right away, where it will proceed with feeding (prey items larger than the spider are first completely wrapped around in silk before being moved). Lacking mandibles, spiders need venom not only to paralyze their victims, but also to liquify the interior of the ones they capture, later sucking up their insides. Males of this species, usually producing only a single thin line of silk to which they stay anchored, get close to females cautiously, initially tapping their legs rhythmically on the edge of the female’s web and only then slowly approaching their possible mate. Should they be successful, they will mate several times, with the female eventually laying a sac of hundreds of eggs underneath a leaf, with both dying after the event.

As the two men shoo away the enormous lizard, the group’s former firer bearer notices something rather strange about where they have decided to set up camp. The floor is covered by very small reddish plants. The orange lighting of their campfire illuminates small pieces of what seem to be dew collected on filaments sprouting from the tiny plants’ leaves, arranged in a rosette. As she moves to take a closer look, she accidentally touches one of the phototrophs, making some of its outer filaments, lacking a droplet of dew at their tops, curl inwards as the whole leaf of the organism moves like a coiling snake in the span of just a few seconds. Surprised, she moves back. She tries to grab the attention of the others, but they are all too focused on preparing today’s meal or paying attention to ensure no more Komodo dragons sneak up. A little afraid but importantly more curious, she touches the leaf of another one of the plants. It, again, curls itself. For the next minutes, she moves around the clearing, touching and touching until she finally gets bored with it.

The others say something to her, probably some kind of warning not to get too far, and she returns. While doing so, she spots a fly, possibly one of the scavenger flies from earlier, landing on one of the plants, rubbing its front legs and putting its proboscis on the dew drop. It moves a bit and, instead of just enjoying the sweet liquid, it is trapped as the leaf wraps around it, more and more tightly. She finds it so strange, so utterly bizarre, that it is hard to wrap her mind around it. The thing looked like the other things around it, things that emerge from the soil and do not move. But there it was, not only moving, but trapping a being that moves in a way that only another being that moves would typically do. Though she does not know it, this has been her first experience with a carnivorous plant and, more specifically, a Drosera burmannii, which, like basil, is widely distributed around this region, even up to Australia.

Carnivorous plants comprise several angiosperms, both monocot and eudicot, that have developed, independently, the habit that justifies their name. They normally grow in nutritionally poor soils that exert a selective pressure for other means of nutrient acquisition, such as consuming animals, exactly what these plants are specialized to do. Despite this, there is great variation among these lifeforms, both in the way they acquire their meals, how they process them, and to what degree they truly are carnivorous. For instance, many of these plants employ pitfall traps, being constructed like tubes (in the case of Sarracenia) or cups (in the case of Nepenthes) with upper lids. Tiny creatures fall inside them and then get digested in the liquid located at the bottom. Even some bromeliads function in a similar manner, acting as reservoirs where prey, usually arthropods, fall in to never come back again.

In regard to digestion, some of these plants actively produce digestive enzymes, which, curiously, appear to only be proteins used for other functions in alternate contexts, rather than being compounds exclusive to these mixed autotrophs (such as chitinases, which, used for defense against fungal pathogens, in these plants acquired importance as degraders of the arthropod exoskeleton). Apart from enzymes, other substances participate in ingestion as well, such as aromatic ones, which might serve not only as toxins but also as anesthetics, dulling the target’s responses and thus making it harder to escape. The digestive environment is usually acidic, functioning similarly to our own stomach, in which a lower pH is necessary for the digestive enzymes to activate, apart from helping, on its own, to break down the tissues of the consumed material.

Besides being full of enzymes and acidic, such environment also constitutes a microhabitat in which several microorganisms live, from bacteria to fungi all the way to protozoans. Not only are they opportunists, taking advantage of collected food, but they also help the digestion process themselves, granting them a status of more than mere commensals. However, should they proliferate excessively, they may cause disease, and so the plants’ digestive enzymes also serve to keep them under control, a balance very similar to what occurs in the gut of animals. Talking about the plants that are not so carnivorous as others, many species of Nepenthes have become more akin to detritivores, primarily living off leaf litter that collects within their cups, but also on the feces and urine of animals much more sizeable than the ones they trap, like bats and other small mammals.

Drosera burmannii is specifically part of the family known as Droseraceae, which, originating around the Neogene (like many other carnivorous plants), contains potentially the most iconic member of this whole group of eukaryotes, that of course being the Venus flytrap (Dionaea muscipula), another small plant that, instead of tentacle-like leaves, exhibits ones that are akin to bear traps, with long, straight filaments rimming their edges that interlock like the bars of a prison cell, trapping unfortunate invertebrates inside as the leaf’s “jaws” close in around them. The waterwheel plant (Aldrovanda vesiculosa) is another representative of the family that, curiously, is almost akin to an aquatic variant of the one just cited previously, also counting with beartrap-like leaves that, quite smaller, lack large filaments lining their edges, having smooth rims. Either way, they function very similarly, closing in on any zooplankton that dwell inside. All of these similarities are of no coincidence, as Dionaea muscipula and Aldrovanda vesiculosa are more related to one another than to any other species within this family, with they likely evolving from a Drosera-like ancestor.

Either way, how do these plants actually manage to move? In the case of the Venus flytrap and the waterwheel plant, this is accomplished via hydraulic mechanisms. When the traps are in a resting state, there is an imbalance between the outer and inner layers of the plant. Distributed among the inner layer, there are small hairs that act as triggers by being filled with very specialized mechanoreceptor cells. When they are touched, they release calcium stored in their interior, kickstarting an action potential that simulates motor cells, springing that imbalance to action, with the outer layer expanding and the inner one shrinking, the two combined processes leading to the closure of the trap, an extremely rapid process that occurs in less than a second. The firing of these signals also starts the synthesis of digestive enzymes, thus advertising that food has arrived and is to be processed.

This whole process may seem eerily similar to how neurons transmit signals between themselves and other cells in the body, and that’s because it truly is. As a matter of fact, plants in general have pathways of electrical transmission, which, though far from as complex as what is seen in animals, are still important, especially due to providing a very rapid way to respond to environmental cues, something very visible in the members of our kingdom, Animalia. In their case, the phloem is an organ with a known electrical pathway, and it is an especially strategic site, since it, like the xylem, extends from the plant’s leaves all the way down to its roots, allowing for quick delivery of signals anywhere along this axis.

In the case of Drosera, instead of beartraps, it counts with leaves exhibiting several filaments that, in many cases, secrete a mucus-like secretion known as mucilage (the dew mentioned before), which is not only sticky, helping immobilize prey, but also drowns them, as it covers the openings to the tracheal system, seen in various arthropods (and talked more about here). Many of these exhibit no or reduced movement, with only the filaments contracting, for example. For small Drosera, however, such as D. burmannii, the outer filaments, as cited previously, lack the dew/mucilage drops, with the leaves thus acting as coils that bring the prey deeper into the plant, where the mucilage-coated filaments are actually present. The mechanism behind the movement in these carnivores is likely different from that of their relatives. Despite also counting with mechanoreceptors and action potentials, these probably do not act to unlock a hydraulic mechanism, but rather to release auxin, a plant hormone associated with growth. Auxin leads to plant cells pumping protons into their cell walls, causing such structures to loosen and expand as they acidify. More growth on the underside of the leaf leads to the effect of it curling, explaining how the whole movement takes place. 

Around the clearing, there are many other interesting plants, with some of the most beautiful likely being orchids. This very diverse family of monocots likely first arose during the Late Cretaceous, and, since then, it has radiated immensely. Despite so many contrasting representatives, these plants share a tendency to be very long-lived, a feature associated with their slow growth and diminished photosynthetic activity when compared to other members of kingdom Plantae. Another common trait between them is their intimate relationship with certain fungi, which are called mycorrhizal fungi, with an example of these fungal organisms being the truffle, discussed in greater detail in a previous entry. These heterotrophic eukaryotes come from various fungal clades and have established mutualistic symbioses with their distant autotrophic relatives several times, adopting different patterns of association. In the case of orchids, the fungi are already present in their seeds, being essential for their germination as they, lacking significant nutrient reservoirs, are initially fed by the fungal companions. As they grow, the fungi play an important role in their roots, increasing their surface area and helping to break down as well as to absorb more nutrients from their growing medium. On the other hand, the heterotrophic partners receive the sugars synthesized by the photosynthesizers.

Different from what is observed between truffles and oaks, the degree of intimacy between the orchids’ cells and that of the fungi is much greater, with fungal hyphae actually existing in tightly coiled shapes within the cells of the roots, leaving from within their vegetal hosts to penetrate the soil. Curiously, these intracellular fungi exist only for a few days, as they eventually are digested by their hosts. Consequently, they live constantly on the move, infecting neighboring cells and later getting destroyed in the one where they originally resided. In some orchid species, the relationship has shifted from mutualism to a form of parasitism, as these plants, completely lacking chlorophyll, are dependent on their fungal associates their whole lives, with one of them (Rhizanthella gardneri), found in Australia, being subterranean for basically its whole existence.

The first orchid we see, Arundina graminifolia, known as the bamboo orchid, is a more usual plant. Quite a large orchid, capable of reaching heights up to 1.8 meters tall, it is distributed around Asia, also making headways into the Pacific islands of Oceania. It lives anchored to the soil, with thick, fleshy roots that serve as storage for many compounds, from sugars to water. Like many previously seen plants, such as ferns, horsetails, and some grasses, it grows from a rhizome, an underground structure that sends out not only leaf and flower-containing stems, but also the just-cited roots. This leads it to frequently form aggregates that can rapidly grow on to cover large areas, such as the one we observe here, and that are also characteristic of plants with this mode of growth.

Close by, there is another orchid of rather similar lifestyle, that being Phaius tankervilleae. The most striking difference certainly is their flowers, with those of the latter being sharper and less rounded, apart from having darker colors. However, other noticeable contrasting traits can be easily noticed: the stem of A. graminifolia is quite tall and slender, while the leaves of P. tankervilleae arise from a bulbous structure, granting it more of a bushy aspect. In terms of distribution, it is found in more areas of the world, ranging from Africa all the way to Oceania. The flashy flowers of orchids serve as very noticeable cues for pollinators, which are attracted by the odors emitted by these structures, the promises of nectar, and by other materials, which, though perhaps not useful directly for the pollinator, can be used by it to feed its offspring or to help build nests. In some cases, these reproductive organs have evolved more deceitful ways of attracting animals, such as by mimicking mates, leading some creatures to try and copulate with them. Of course, that whole ordeal is just a waste for the bamboozled metazoan, but as long as it visits another flower, it will have spread the autotroph’s gametes, ensuring the success of the strategy.

If one looks at the trees, even more orchids can be found! These are of the species Bulbophyllum lobbii and just testify to the amazing diversity of this family of plants. More akin to P. tankervilleae, it has fat bulbs from which emerge its leaves and a flower that is also very sharp in appearance, with its lowermost petals forming an arch that ends with them almost touching. Unlike the terrestrial forms, epiphytic ones, such as this, exhibit their very own specific traits that allow them to survive in a habitat that is much more challenging in terms of nutrient acquisition. First of all, their roots are thin, being called aerial roots, and not only do they act as an anchor to the bark, but also extend for distances up to 1 meter, maximizing how much they can gather from the surrounding environment. At the cellular level, such roots are covered by a dead layer of cells, absent only at the tips, where the organ grows. Normally dry, this layer can rapidly fill with water during rainfall or when moisture levels are high, functioning almost like a sponge. In the opposite conditions, it protects the living part of roots from water loss.

Apart from the difference in roots, the leaves of the epiphytes are generally thicker and succulent, constituting an important means by which water is stored. Not only that, but these also have fewer stomata and a peculiar cycle of stomata closure and opening shared with many plants that dwell in dry habitats. During the day, the plant photosynthesizes, but the stomata remain closed, avoiding water loss but inhibiting a more substantial influx of carbon dioxide, a substrate of photosynthesis. At night, the stomata open, since, at this time, there is less evapotranspiration. The plant takes up the carbon dioxide it needs, accumulating it as an acid so that it can be used during the day, even though the stomata are closed. Most plants undergo the opposite cycle, keeping their stomata open during the day and allowing the influx of carbon dioxide to fuel their photosynthetic activities. During nighttime, the stomata close, since photosynthesis stops, and they being open act as a gateway for losing water.

Finally, going back to the hominins, the grieving female has been feeling ever hungrier lately, apart from having noticed a lack of periodical bouts of vaginal bleeding coupled with an enlargement of her breasts. She is pregnant. Growing inside her is a product of the fusion between her own genomes and those of her deceased mate, but more than just a fusion, a unique arrangement of the genetic material of its progenitors, an amazing process that harks back to our archaeal ancestors. Interestingly, very few mammals undergo the process of menstruation, and a few of these are apes, certain bats, and the curious creatures known as the elephant shrews (another group of afrotherians). Why this phenomenon occurs is not completely known, but it is likely associated with the degree of placental invasiveness, with these synapsids having more invasive placentas, something that can pose a significant risk for the health of females in the form of the pathology known as placenta accreta (in this condition, the fetal organ may not only transgress the uterus completely, but invade neighboring structures, such as the bladder and the rectum). The episodic process of endometrial adaptation for embryonic implantation produces boundaries against the expanding and infiltrative tissues, limiting the invasive event, but generating the shedding of this layer every time there is no or unsuccessful implantation. Apart from this, this desquamation of the inner lining of the uterus serves to eliminate failed embryos, avoiding maternal investment into offspring that will not develop.

Even so, the placenta is still a remarkable organ that ensures that the fetal and maternal circulations are completely separate, while simultaneously allowing for the diffusion of gases and nutrients. Despite this separation, some pathogens are capable of crossing from the mother to the baby, potentially inducing severe congenital anomalies. A few of the organisms capable of doing so are herpesviruses, a group of large, DNA-based viruses possessing icosahedral capsids externally covered by an amorphous proteinaceous layer and even more exteriorly enveloped by a lipid membrane, derived from the cells they parasitize. Infecting both reptiles and mammals, these lifeforms, constituting the family Orthoherpesviridae, likely arose back in the Permian and have since then co-evolved with their vertebrate hosts. Many have specialized in infecting primates, and later some became parasites of hominins.

One of these is the varicella zoster virus, which has likely coevolved with hominins since their origin. It is highly contagious, being spread via aerosols and thus initially replicating in the upper respiratory tract. From there, it makes its way to lymph nodes through professional antigen-presenting cells (better explained here), where it proceeds to infect lymphocytes, some of which have cellular markers that make them migrate to the skin. These leukocytes, inadvertently carrying the virus, disseminate it among skin cells, giving rise to the characteristic cutaneous lesions that are well-associated with chickenpox and that also are another path for transmission. Fortunately for the host, viral replication is soon controlled, but the pathogen stays dormant within the nucleus of certain neurons, which they access by entering the nerve endings of such cells, contained within the skin. This dormancy allows these organisms to become active once again at a later date and, though immunity develops against new infections, the body is never able to completely eliminate the residual parasites, allowing the varicella zoster virus to be continually spread from generation to generation, manifesting mostly in children (the initial infection) and in the elderly (reactivation).

Due to this ability, the Homo floresiensis have maintained this virus since their ancestors first became stranded here and, no matter how many in the population get infected, it always comes back, in one way or another. In some cases though, this herpesvirus affects humans even earlier, passing from the mother to her baby. This can be disastrous, as the pathogen induces several malformations and developmental anomalies, such as poor growth of the cerebral cortex, atrophied limbs, malformed digits, scars following areas of nerve innervation (similarly to the presentation of reactivation), cataracts, among many others. Fortunately for the developing human within the womb of this female, its mother contracted this disease many years ago, and she is not poised to undergo a reactivation for some years still, making the embryo safe.

The other one is called Cytomegalovirus. Unlike its relative, which often causes symptoms, this virus goes unnoticed in the great majority of cases, being spread by bodily fluids, such as saliva and urine. A great part of its large genome is devoted to immune manipulation, with it counting with several proteins and non-coding RNAs that not only promote evasion of the immune response but also enhance it under certain conditions, all effectively for the benefit of the parasite. This great adaptability explains the asymptomatic course of infection, but also this pathogen’s success in infecting a great percentage of the population of Homo floresiensis and also of modern-day humankind. Similarly to the varicella zoster virus, though, it also remains dormant in the nucleus of cells, but, instead of neurons, it lies latent in cells of the bone marrow, with infected cells becoming enlarged and with nuclei full of viruses, which gives these structures the appearance of owl eyes as a result of the viral inclusions within. Capable of passing through the placenta, most infected babies show no anomalies, but some may develop hearing loss and others still can suffer from seizures due to cerebral calcifications, as well as hepatitis, retinitis, extramedullary hematopoiesis (destruction of the original bone marrow leads to hematopoietic progenitor cells, which generate red blood cells, leukocytes, and platelets, relocating to other sites, such as the liver and spleen), pneumonia, and various other manifestations.

Apart from the possibility of transplacental infections, gestation is a cumbersome event, especially when it comes to birth. Both humans and smaller monkeys have a complicated birthing process, as primates tend to have proportionally larger heads. In the case of the great apes, their larger body size leads to wider vaginal canals that ease birth. Humans and other, more derived hominins, for that matter, despite also being larger (not so much in the case of Homo floresiensis, however), are bipedal, a type of posture that puts constraints on the diameter of the birth canal and, apart from this, possess, like the great apes, sturdy, rigid shoulders that are difficult to pass through, making the nascent baby rotate in order to come out. Births became even more complicated with the increase in brain size observed along the evolution of the hominins and especially with the appearance of the genus Homo. As a result, birthing has turned from a solitary practice to a social matter, in which the mother requires assistance, especially due to the rotated position of the child, which makes it hard for the mother to help her baby with her hands due to compromising the birthing stance she was originally in (something that could have severe outcomes, such as rupturing the newborn’s spinal cord). Apart from these behavioral adaptations, pelvic changes and more underdeveloped young, with heads still not too big, but much more helpless at birth, have been gradually selected for, trends that have gotten more pronounced with further cerebral expansion in species like ours and Homo neanderthalensis.

Curiously, the complications involved in birth might be behind some of the reasons we develop acne, a disease characterized, in part, by the inflammation of a specific type of sebaceous gland, which, like sweat glands, is another feature of the glandular skin of more derived synapsids. While this condition typically occurs during adolescence, largely driven by increased androgens, these glands are also most active at another time: during birth. Besides, they are encountered in higher densities in the forehead, face, as well as in the shoulders, areas that are a significant impediment for the passage of the newborn, as just said. Consequently, it is likely that humans developed a significant increase in these glands to facilitate the passage of babies, which were made slimier and thus got through more easily. Apart from increased production of sebum, neonatal sebaceous glands also produce a white, slimy substance known as vernix caseosa, which not only reduces friction between the newborn and the vaginal canal, but also has antibacterial properties and potentially aids in the conservation of both water as well as temperature.

Well, moving away from obstetric matters, many humans feel abnormally hungry for another reason: tapeworms, more specifically those of the genus Taenia. Fortunately for the Homo floresiensis, a lack of adequate intermediate hosts in Flores had rendered these platyhelminths extinct on this island. Originally, humans and other hominins became infected with these creatures after ascending in the food chain and consuming the meat of larger herbivores (like bovids), which acted as intermediate hosts. The definitive hosts, once only carnivorans like felids and canids, now also included hominins. Well, it is important to explain the life cycle of these organisms and elucidate how each type of host is associated with them. In definitive hosts, sexual reproduction takes place, and it occurs via the adult worm, a creature that may be extremely long, usually around a few meters in length, but capable of growing to whopping 25 meters long in the human-infecting species Taenia saginata. The thin body of these invertebrates (a hallmark trait of their phylum) is divided into several segments, which get progressively wider as one gets more distant from their heads, and allows them to absorb, along their entire surface, nutrients from the surrounding medium, which is particularly rich in them, since they survive in the intestine, a long and convoluted organ that also accommodates their often very long bodies. As such, they lack a digestive tube and get all the food they need directly from their skin.

Their heads may vary quite a bit between species and are essential for providing an anchor point through which they stay attached to the intestinal wall. In the case of Taenia solium, another human-infecting species, the head counts with four large suckers positioned behind a ring of chitinized hooks. In the case of T. saginata and Taenia asiatica, two closely related species that likely diverged through the migrations of Homo erectus, they lack hooks altogether, only sporting the four suckers, which are positioned on top of their heads, rather than on the sides, as occurs with T. solium. Either way, each body segment is an independent reproductive organ, producing both male and female gametes, which fuse to form eggs. Consequently, Taenia generally undergoes auto-fertilization, and the young it produces, though different from itself due to the genetic rearrangements of meiosis, are all children of a single progenitor. The more mature and gravid segments are also the wider ones, being released from the posterior extremity of the worm and ending up in the host’s feces, while, from the head, more segments are constantly being formed and expanding towards the tail.

The eggs, microscopic and released in the excrements of the definitive hosts, disseminate around the environment and are eventually consumed by the herbivorous, intermediate hosts (in the case of T. saginata, these hosts generally are bovids, and, for the two other human-infecting species, they are primarily swine). After being consumed, the eggs hatch, revealing a larva adorned by six hooks that drills through the intestinal wall and disseminates through the body of the parasitized animal via the bloodstream, usually lodging itself in muscle tissue and shifting from a purely solid form to a cyst-like structure in which the head of the worm finds itself suspended in liquid. When the intermediate host is consumed by a predator (in the case of these three species, usually humans), such cysts enter our intestinal tract and the head of the worm evaginates out from the fluid in which it was, adhering to the gut wall and proceeding to grow, eventually getting meters long and with many, many segments. T. solium, though, is more dangerous to Homo due to its ability to infect us even as eggs, transforming us into intermediate hosts. While the worm is unable to complete its life cycle should this occur, the larvae can lodge themselves in various organs, from muscles all the way to the brain, potentially causing severe neurological manifestations.

As the night progresses, the five finally appreciate their rat roast, which they completely devour fairly rapidly, even breaking the bones and consuming the marrow within. The grieving, pregnant female eats the most, and the others appear surprised by her ever-increasing appetite. Eventually, they go to sleep. One of them usually stays awake for some time before exchanging duties with another. When they lived in a larger group, sleeping was a safer matter, but now they rarely rest appropriately, quickly waking up at the slightest sound of a stick breaking or of nearby footsteps. Despite this, with one other female standing guard, holding her fiery stick high, the pregnant female sleeps fast. In what feels like seconds, she is seeing the clearing again. Strangely, none of her companions are present, but that does not bother her for some reason. The campfire has already extinguished itself, leaving only charred wood and a soft smoke that rises from the burnt and black materials.

The woodland is silent, and there is only the quiet sound of the wind against the leaves, moving slowly with the night breeze. She looks up and sees a bright full moon, illuminating her surroundings in an ethereal shade of whitish blue. But then she hears something rustling deeper amongst the trees. It sounds like many feet, many feet rapidly and frenetically moving. Squinting, she makes out figures just like her, but much taller and as black as the night itself, melting with the shadows as they move. Suddenly, there is no calm on her mind and she grabs a stick while turning her back to a tree. Tensely staying guard, she waits. Around her, the sounds seem to be decreasing, but, horrifyingly, it seems the black figures are now turning to her, watching her with black eyes and emerging from the trees like ants leaving an ant hill. It is then that she sees her love. How could it be? Him alive amidst this nightmare? But there he stood, arms open, ready to embrace her like he had warmly done so many times before. Gripping her stick more intensely, she calls out to him, but receives no vocal response: he only gestures for her to come closer, with his arms still wide open. Around them, the black figures with black eyes continue watching, unmoving, unbreathing, and unblinking. Without thinking further, she runs. She cannot keep her love waiting any longer: he cannot wait, she cannot wait. It is then that she wakes up, inches away from her deceased mate.

It was indeed all a dream. To her, it is obvious now, but for instants it seemed all too real, all too material: something she had almost grasped. Looking around, she sees it is already dawn and the first rays of the Sun filter down from the canopy. Her companions are asleep: it appears that the last one to stand guard slept on the job. Fortunately for them, it was a calm night. Well, for her not completely. Grabbing a wooden stick, she tries igniting it on the fire they made last night, but it is truly gone, and even the smoke has already dissipated. Grabbing one of their rocks as compensation, she makes her way through the woodland carefully, but not scared either. There is somewhere she needs to go. After some minutes, she gets there: a beach. Not exactly the same one she used to go with her mate, but nevertheless, close enough. She watches the rising Sun and its warmth heat up her body and the sand beneath her feet. It is almost as if he were really there. And there she stays, embracing in mind what she cannot in life, for that is all that was left.

Some time passes, and she decides to return, especially before her peers start looking for her and potentially engage in unnecessary dangers. Just as she is about to return to the woodland, she notices something in the corner of her vision. Two strange structures, aground on the sand. Curious as she is, she approaches, initially believing the two objects to be stranded sea creatures, perhaps something she can even eat, for, with her current hunger, she is rarely satiated. However, she is surprised by what she encounters: two hollowed-out logs. While encountering logs on the beach is not something rare in itself, she finds the shape of the logs very strange, since they are unlike any tree she has ever seen: no tree is hollowed out like that. Then, she is surprised by yet another finding: footprints much like her own, but much larger, almost double hers. Immediately, the large people of her dream return to her mind as she looks with apprehension towards the portion of woodland where the footprints are headed. What had arrived on her island?

The answer is ourselves, Homo sapiens. Originating around 300 thousand years ago in the African continent from descendants of Homo erectus, our species migrated out of the homeland many times, especially through environmental corridors made available by the constantly fluctuating climate of the ice age. However, none of these bore significant fruit until now. The reasons are not particularly well known, but a combination of competition with fellow hominins, such as Homo erectus and Homo neanderthalensis, together with poor adaptability to new environmental conditions, and interruption of population flux with the individuals remaining in Africa likely all contributed to the failure of these early expeditions. But recently things have changed. Potentially as a result of increasing human occupation of Africa itself, the populations of Homo sapiens have become increasingly adapted to new habitats and, coupled with possibly greater disputes, they have not only successfully left Africa once more, but now have achieved stable populations beyond the native continent and, in the following thousands of years, will occupy all continents with the exception of Antarctica.

The Southeast Asian islands have already been reached and, unlike what happened with Homo erectus, probably not in a purely accidental manner, with the production of rudimentary boats that, even so, are capable of crossing vast stretches of water. Flores’ life will not leave this encounter unharmed, and many of the animals we have seen along this tale will disappear, such as the Leptopilos robustus, Stegodon florensis insularis, Trigonoceps, and many others, including several rodents unmentioned. How exactly all of these disappeared is not clear, but hunting by recently arrived humans probably led to the extinction of larger creatures such as Stegodon, a keystone animal that, by serving as food to the avian scavengers cited, caused a widespread environmental collapse, exacerbated by more of its actions, such as spreading seeds. Komodo dragons, though, would curiously survive, potentially by dwelling more around beaches and scavenging on stranded aquatic creatures. Competition with Homo sapiens and possibly even predation by their larger relatives could have wiped out the tiny hominins. It is of great irony that the same that brought down their existence were also the ones to later remember them, by excavating their remains and once again contemplating ancient tales.

Human-associated extinctions would not occur exclusively on Flores, but follow a pattern observable across the world. Around the planet, megafauna would be driven to extinction, especially as large mammals encountered a novel predator of ingenious ability and craftmanship that reproduced independently of them as a result of its resourcefulness, very unlike more traditional predators, whose populations are tightly correlated with those of their prey. Only the megafauna that coevolved with Homo sapiens were able to more efficiently survive the onslaught, such as the big mammals of Africa, many of which are still alive in the present day. In most areas elsewhere, though, animal communities became strangely empty, devoid of the larger creatures that were once part of them.

And so we finally reach the end of our journey, or so it seems... Dear reader, we have, in fact, just begun. All of these stories, as already implied in the first of them, represent just a tiny slice of the Phanerozoic and an even tinier slice of Earth's history. Even if we had the pleasure of exploring tales from all known paleontological settings, you can rest assured we would unfortunately still be missing quite a bit, for time is not very forgiving. Even so, as we progress on this farewell, keep in mind the habitats and the organisms presented truly did exist (some of them still do!), and, even though these tales may not have happened exactly as narrated, they were very much as real as you and me. This entire project strives to drive this point home and to also make it clear that, despite much effort, a whole view of these long-gone places will remain unattainable. Do not let that let you down, however, for remember that both of us are still in the Phanerozoic. All that has happened is intricately connected to what happens in an indivisible mesh that continues to extend, into and into the future. As I write and you read, many tales are ongoing, every day, every hour, every minute, and every second, both macro and microscopically. And we are part of such tales, as are the other beings and environments around us. So, with this, we end, but not to finish, only to begin once more.

***

1-Homo floresiensis

2-Papagomys armandvillei

3-Drosera burmannii

4-Gasteracantha taeniata 

5-Brachyceran fly

6-Ocimum basilicum

7-Leptopilos robustus

8-Malayopython reticulatus

9-Megapodius reinwardt

10-Heleia wallacei

11-Eucalyptus urophylla

12-Bulbophyllum lobbii

13-Otus magicus

14-Otus alfredi

15-Cinnamomum burmannii

16-Stegodon florensis insularis

17-Corvus florensis

18-Phaius tankervilleae

19-Arundina graminifolia

20-Varanus komodensis

21-Attacus inopinatus

22-Mosses

23-Gekko gecko