The Firmament

290 million years hence, the grasslands to the southwest of Serinarcta are semi-isolated from the savannah woodlands of south-central and south-east Serinarcta, thanks to a thickly vegetated, low-lying swampland region that divides them south of the Centralian Sea. Animals which prefer dry land rarely make the trek between the two, which covers several hundred miles of quagmires and impenetrable, waterlogged forest, and so the two regions have many of their own endemic species. The savannah woodlands are far larger and more continuous than the upland plain at this time; though drier now than at the start of the hothouse, rainfall is still regular here, and the sparsity of trees is more due to intense browsing pressure from gigantic skuorc herbivores than constraints of climate. The upland plain region however truly is more arid. Though this is still only relative to the rest of this very wet world, this high-elevation region quickly loses much of its rainfall to lower elevations, and has a very deep water table that is generally out of reach of plants. This is because most of the upland plain has been lifted almost a mile above sea level through the active growth of numerous cementree colonies over the last ten million years. These uplands were the epicenter of the spire forest, and where it has existed the longest. Though their descendant biome, the sky islands (which are fundamentally just very large, very old spire forests) are now found globally, only here have they reached such immense size to have virtually lifted the earth toward the heavens on a continental scale.

Millions of years ago, the ancient spire forests of the upland plain fused on a massive scale, forming a rising plateau. Today, however, the cementrees responsible for this remarkable construction are now only sparsely distributed; most of the plateau is now colonized by plains grasses and herbaceous plants. This change has come about because the plateau has become a victim of its own success. It grew so large and continuous that large grazing animals were eventually able to reach its summit, and there browse down the trees' canopy at a faster rate than it could recover. Today the trees which built the region called the firmament are reduced to isolated patches on terrain too steep for gantuans to reach them. Elsewhere, this entire region now sits atop the peak of an immense, extinct sky island.

The firmament - a word that means "heavens" - now holds the title for the highest elevation on Serina, with its highest summits having reached nearly three miles high, and an average elevation of 8,500 feet, though it is now eroding without continued tree growth to compensate for weather. Today, the firmament's dominant biomes are montane grassland and shrubland, habitat types that do not exist anywhere else on Serina. Rainfall is predictable, but much of it drains away instantly through the cracks of the rocky soil, meaning vegetation must be adapted to collect it immediately and deep-rooted trees are rare, as it is futile to take water from the ground when it doesn't remain within reach. Solar radiation is intense at this altitude meaning animals usually have black glare-reducing facial markings, highly pigmented eyes, and dark skin. Temperatures are colder here than anywhere else, despite the equatorial location, due to the height of the land. It can even drop below freezing in the highest reaches of the plateau occasionally at night, when flurries of snow will fall and dust the grassland in white that vanishes shortly after sunrise.

Though the firmament is now inhabited by some animals which evolved in lower landscapes - such as the gantuans and skullosi which contributed to the extinction of its trees - many of its inhabitants evolved here from ancestors that could reach the peaks of the sky island before it became accessible to others. The most numerous grazers of this plateau are giraffowls, whose flying adolescents fluttered here millions of years ago and simply never left. And among them there can be found the fowlpaca, the giraffowl with the most complex manner of rearing its young.

Fowlpacas are a basal giraffowl, branching off from the early ancestors of skybreakers, capricocks and the Zarreland clades. Physically, they are unremarkable; males have only very short, paired beak horns and rarely have different colors from females. They are the most cursorial giraffowl, however, and their very long legs end in paired hooves. They are herbivorous, cropping grasses on the firmament in vast herds that run over this sky-high plain like antelope. And perhaps because they evolved to live in this specific habitat type, they all have flightless young which do not disperse far from their mothers until several months old. Due to the cold nights, chicks will return to the mother's abdominal pouch for days or even weeks after emerging from their pupal sacs, and are cared for by her to a remarkable degree for this clade. Though most are still born with wing feathers and an elongated digit to support them, they cannot fly, and lack strong muscle attachments on the breast to allow it. Chicks take longer to hatch, and do so at a more adult state of development than in other giraffowl. Fowlpacas take this increased parental care to its greatest extreme; they have evolved a fatty, milk-like secretion which their newborn young lick from the walls of the pouch in their first few weeks of life for sustenance, allowing them to rapidly grow without leaving the safety of the pouch at all. This secretion is derived from a lubricating oil produced from glands inside the pouch which helped keep the eggs moist and prevented them from sticking to the walls of the structure during incubation. They are thus the first birds to truly lactate, rather than produce similar food products internally for their young. This gives them a great competitive advantage over many other animals in this less hospitable climate, and so these giraffowl remain successful even in the face of a few recently-arrived thorngrazer competitors. By sheltering their young in this way, they are also protected in their earliest days from predators, which are not absent, even on this heavenly plain.

Drackals are a family of small vultrorcs, and the more basal branch of this skuorc clade. They are only distantly related to the gigantic devils, which specialized as gantuan predators and robust scavengers; though the two lineages have a common descent from the four-horned petratel, they diverged 13 million years ago. Species range from less than 90 lbs to around 250 pounds, positively diminutive in comparison to their cousins, but are far more athletic and able to chase smaller and much more agile prey species. They are immediately distinct from nearly all other birds for having evolved external ears; these are closest to the sound-amplifying feather tufts of the unrelated (but convergent) griffons in Serinaustra, but are more specialized and feature a non-mobile pinnae around the ear opening, from which a dish-shaped ring of stiff feathers grow. Many small drackals rely on their acute hearing to ambush small burrowing molodonts in tall grass.

Drackals' limbs and torsos are strongly dog-like in appearance, and like them they are adapted to endurance running, using persistence rather than bursts of speed to pursue fleet-footed prey animals such as giraffowl and crested thorngrazers to exhaustion. They have powerful crushing jaws and these are their only real weapon, as their claws are fairly blunt and their forearms not flexible enough to use them to grasp. Unlike devils, the entire body save the snout is feathered, though the plumage is very short, wiry, and resembles hair in almost every respect, even in its disorderly, random distribution across the skin (most bird feathers grow in aligned tracts.) There are no scutes on the legs, nor even on the toes, rather canid-like paw pads are present on the bottom of the feet to provide traction. Long, thin tails serve as rudders to let these hunters turn on a short radius and keep pace with their quarry as it dodges and weaves in its effort to escape. Unlike canids, however, drackals are solitary and territorial predators, and thus despite their convergent evolution, their ecological niche is more similar to large solitary felids like tigers than to wolves. Even so, these skuorcs are less antagonistic of each other than devils, and while those animals will readily eat their own young, female drackals engage in a high degree of parental care and attend their young for up to a year before they are fully independent. This is the strongest social bond that exists in the species; males and females meet only to mate and then quickly part. Like devils, drackals have small horns above their eyebrows, but in this lineage they are a sexually dimorphic trait and are absent in the female. Males use them for display and to mark territory on bushes and boulders; a channel runs along their length and connects to a scent gland near the eye, letting them deposit odorous secretions around their territory to keep rivals away.

The alpine drackal is one of the largest carnivores to live on the firmament, Serina's highest alpine plateau, where a lack of other competitors has allowed it to reach a robust size  - it is the biggest example of its clade. Giraffowl such as the fowlpaca are its choice of food almost exclusively. It catches them with a debilitating bite to the neck, after running them to exhaustion for many miles. Both sexes store food by burying it below ground; females will also drag kills for long distances back to a den site where they hide their young for the first few months of their lives.

~~~

The dens of the alpine drackal are not necesarilly dug out by this animal itself. For the structure of the firmament comes with pre-built housing, if you follow the lead of other animals which have done the work to reach it.

The city sniffler is a small trunko descended from the spitfire sniffler that is common to the montane grasslands of the firmament, where it constructs elaborate burrow systems that can penetrate through the surface soil and reach deep into the structure of the sky island itself. Sky Islands, when alive, are pitted with hollow spaces - former chambers inhabited by the trees and ant colonies. Even in the firmament, these still remain, albeit in a semi-fossilized state. They provide a pre-built labyrinth of tunnels, protected from temperature extremes and most predators, and all that must be done is to chisel out small openings between to connect them. This is where the city sniffler lives. The vast hollow space it can make use of below ground becomes a veritable hidden city, supporting huge colonies of hundreds of animals, and further divided into sleeping areas, food storage, latrines, and tunnels used for long distance movements between colony territories, allowing young to disperse without risking the dangerous world above, where their small size leaves them vulnerable to attack by flying birds. Other animals, like the drackal, readily usurp parts of the sniffler's city for their own uses, forcing the snifflers to continue chipping away and accessing new tunnels. 

This sniffler, though it lives below ground, is not a particularly well-adapted burrower. Like all trunkos, it lacks any forearms at all, and its trunk is soft and not useful as a shovel, nor is it beak long enough as in the distantly related snorts. Initial burrowing through soft surface soil is done with the hind claws, and sharp spiny quills along the rump can be puffed out to fill the tunnel space behind them, preventing predators from sneaking up behind as they dig. Further, the rump of this trunko is brightly colored with red, gold, black and white plumage - a warning sign that not only is this sniffler sharp, but it is still poisonous!

The city sniffler gets its poison from external sources. Though it is safe below ground it doesn't find much food there, and so it must leave the tunnels to find both food and the materials it applies to its quills as a defense. Bands of ten to twenty, sometimes more, leave the city together for safety in numbers. These foraging groups collect a wide variety of food; they are omnivorous, and will eat arthropods, worms, grass seeds, roots, and fungi, and may opportunistically find and collect all of these things and more when above ground. Snifflers are the only trunkos that will carry food in their neck pouches, and the city sniffler shares this behavior with the skyskipper, each member of the group filling its pouch with tidbits that will be taken back home and stored or distributed among others who did not forage this time. They also collect things that they cannot eat; one such thing would be herbs with toxic sap - even toxic plants called flameflowers that evolved to kill thorngrazers - that are clipped between the toe claws and carefully kept out of the mouth or the pouch. These are later pulverized with stones within the burrow complex, and the pulp groomed carefully into everyone's feathers before they leave the tunnel, providing a toxic defense that at best renders them utterly disgusting to predators, and at worst will kill them if they bite one.

Communication is excellent within the colony, and sentries are posted at burrow entrances all around the foraging party, each of which will emit a shrill alarm call if a predator is spotted, telling the party to take defensive action. If a burrow escape is nearby, they will flee down it and avoid a fight altogether. Often, though, at least some members will be caught in the open. Their defense is to tuck their heads in the grass and raise their flashy spiked rumps in their attacker's direction, a signal of their danger that is usually respected - if not, the sniffler rushes backward and sticks its enemy with its quills, delivering its herbal toxins into the sensitive parts of its face. The front of each city sniffler, meanwhile, is a well camouflaged banded green and brown pattern: this conversely hides the sentries as they stand guard in the grass, their bright butts hidden in its cover.

Tool use is well-developed in this gregarious and socially complex trunko. Not only are rocks used to crush poisonous plants, but they are also used as pick-axes to dig out and connect tunnels in the "city." Sharp, flat rocks are favored, and may even be flaked on purpose into better shapes. Though cementree structure is very strong, it can nonetheless be shattered with repeated blows to a small area, and teams of city snifflers enlarge their cities by systematically hammering weak spots to open up entrances into new chambers. These snifflers live in multi-generational colonies which may persist for thousands of years, and over deeper time, these cities can become immense subterranean mazes going down hundreds of feet, and extending for miles horizontally. And near the very bottom of the complex, the city sniffler maintains perhaps the most remarkable part of its city: the farm.

City snifflers are the second trunko species to discover agriculture, and theirs is arguably even more complex than the farmackle's. Though they enjoy a wide variety of food, most of what they gather from the surface world is supplementary - novelties discovered while looking for something more important. Over 40% of the city sniffler's diet is made of fungi; specifically, mostly just one kind of mushroom. Another 40% is made up of beetle larvae - mostly, from just one kind of beetle. Only the remaining 20% is comprised of odds and ends from outdoors. Fungi and beetles are both reared intensively in the lowest levels of the city on a steady diet of... giraffowl dung, which is what the foraging parties are seeking when they leave the city. It is a very abundant resource, and one rich in nitrogen and other nutrients, albeit not immediately usable to the sniffler. To make use of its potential, it relies on allowing other, simpler organisms to grow within vast underground fields of this manure, which is regularly turned and aerated to keep it healthy for the fungus and the beetles to survive within it. This agricultural system has evolved over millions of years, and originated incidentally, with opportunistic organisms growing within the sniffler's own latrines, and happening to find their way back into its own diet. At some point, these clever creatures put two and two together, and seeing the wide variety of edible insects and mushrooms that spring up from the manure of other animals, happened to bring some down into their larders and learned that these foods will proliferate even more quickly in the sheltered safety of the city. Now foraging parties can limit their time above ground to an absolute minimum; they have one objective, to gather dung, and it is widely available and not hard to find. Then, using this single external resource, the colony can grow enough food for the entire city to eat in safety. Food security is assured for the city sniffler, and this is what allows it to be so gregarious - the boundaries between colonies are muddy and difficult to discern, merely blending together from one part of the city to another, as there is no shortage of resources to fight over, and so little reason to keep to isolated groups.

Of course, wherever food is gathered in abundance, thieves will come to take it.

~~~

Colonial insects are very numerous over Serina's grassland environments, and even the colder climate of the firmament doesn't discourage them. Ants, of course, are ubiquitous everywhere. But there are others, too. Vermites, a clade of eusocial, neotenic, and vaguely caterpillar-like crickets, are specialized herbivores in ways ants are not. They feed on the cellulose in dry grass, and as such are important decomposers. In hotter climates, they build ventilated earthen mounds - they are analogous in their roles to true termites( which are of course absent on Serina), and have come up with many of the same solutions to survival. But on the firmament, it isn't necessary to disperse heat - rather, it needs to be maintained through cold nights. So here vermites live well below the ground, in matrilineal colonies which may persist for centuries, insulated deep under the surface. They make use of the same hollow spaces within the underlying reef of the extinct sky island as the city sniffler, dissolving tunnels in the structure with their powerful stomach acids. Here, they are safe from many predators. But not all.

The varc is a small but robust petratel, descended from the same ancestors as the vultrorcs, but several million years before their last common ancestor had evolved. Weighing up to 150 pounds, it is a low-slung, plodding animal with a massive beak which it uses to dig though packed and rocky earth. Varcs are largely insectivores, and are specialized to open up vermite nests, though they will eat any sort of meat they come across without any hesitation. When a colony of vermites is detected, the varc literally just gnaws at the ground, tossing mouthful after mouthful of soil until it has dug down into the nest. Then it uses a flat, wide tongue almost like a sponge to collect thousands of the insects as they crawl every which way, eating several pounds of them - perhaps a million individuals - in a sitting. The front half of the varc is certainly fierce, and its bite - adapted to gnaw through stone - can easily break the face of nearly any predator that might try its luck. It is more vulnerable while face-down in a hole, eating its prey, and so its tail is also lined with a defensive brush of sharp quills which are swung back and forth as it feeds to prevent would-be attackers from trying their luck while its back is turned.

This skuorc is not an obligate insectivore. It also feeds on vertebrates, especially molodont nestlings, though generally only incidentally. It is an enemy to the city sniffler, but not usually a predator of it, as it is much less maneuverable in the confines of burrows and cannot easily catch them. It's main goal, when infiltrating a city, is to reach the farm in the basement level and gorge itself on the sniffler's own food supply of beetle larvae. Greedy and rapacious, a single varc can empty a small farm in a short time, so the snifflers aggressively group up to defend their resources, pelting the varc with stones and collectively trying to cave in sections of the city to bury it alive. Usually, this means the varc must limit itself to brief smash and grab attacks, fleeing before back-up arrives.

The varc is not alone in feeding on colonial insects on the firmament. It shares this landscape with a weird molodont called the eartheater, a species that is also not entirely restricted to a diet of small bugs.

Eartheaters are thorngrazers, but weird even by their standards. They are long-legged, but short-necked. They have huge skulls, but small teeth and a low bite force. Most of the body is hairless and warty, except for a small patch of striped fur on the ridge of the back. They walk around, head down, always smelling the ground. They appear, for all intents and purposes, to eat the dirt itself, rapaciously swallowing mouthfuls of soil. And they have two large, dagger-like fangs, each one some 13 inches long.

These thorngrazers are the closest relatives of the thornsaber, and though there is a family resemblance, the two groups - which are only 4 million years divergent - are wildly different in behavior. Eartheaters represent an early variation on the carnivorous monstrocorns that specialized in eating invertebrates. While thornsabers hunt and bring down other thorngrazers with their saber teeth, eartheaters dig in the soil, finding dense concentrations of bugs and worms with a strong sense of smell and taste. These are the only thorngrazers with a long tongue in adulthood, and they use it to taste the ground as an extension of scent to find food, much like a snake.  When food is detected, the eartheater digs down with its jaws, particularly its two fang-like tusks, which are blunter and splayed more outward than in their fiercer relative. Its primary prey are vermites, as they are found in high, concentrated density, but it enjoys earthworms and the odd grub, too. It is unusual for its method of feeding, which appears extremely lazy. Rather than single out individual insects, or even lick up a bunch at once, the eartheater simply chews up and swallows the soil around them, ensuring it doesn't miss even one bit of protein. The inedible components of the dirt are separated from the food within its gut and discarded through its droppings, which have the consistency of wet sand. As it eats far more dirt than insects, its digestive system is virtually always hard at work, and it poops several times a minute in small quantities, allowing it to very effectively mark its territory... almost every square inch of it. These are one of a few species that is native to both the savannah to the east and the firmament to the west, as well as the intermediate wetland areas, as all three habitats provide abundant insect food. The behavior of this animal differs in different environments, however, as a result of interactions with other species that are absent in one but not the other.

The eartheater, as it occurs on the savannah, is a timid animal, and could even be described as cowardly. Even though its jaws are weak, it could still deliver a painful blow with its fangs, and yet examples of the species here almost always chooses to run from confrontation with other animals, and for this reason it only very rarely scavenges on carrion, and does not engage in significant predatory behavior. It feeds mainly at night, and in doing so avoids detection by more aggressive competitors or predators including gantuans and its own relative, the thornsaber, which will occasionally consume it. High on the firmament, on the other hand, the eartheater has few predators and less to fear. In this habitat, it grows up to 30% larger and is highly aggressive, even killing the very young calves of other thorngrazers and eating them to supplement its diet. The reason for this shift of temperament is surely due to having less to fear from bigger animals, but the broader diet may be related to the vermites of the firmament not constructing elevated mounds which are easily located as on the savannah. Here, they live deeper below ground, and are much more work to locate.  Not only this, but the varc lived here long before these thorngrazers found their way up the slopes far more recently, and it was already better-adapted to reach them in deep subterranean nests. All of these factors may be pushing the eartheaters here to reconsider their insect diet and return, to some degree, to more predatory roots. 

~~~

Unlike varcs, eartheaters pose little threat to city snifflers - they lack the adaptation to dig down to reach their farms. But there is one singular predator that threatens those small and gregarious trunkos even without being able to dig below the earth. It does so by completely avoiding touching their poison hides at all, and such, is one of the only animals to eat them outright It is the upland impaler. This 4 foot tall, recently flightless sparrowgull is a descendant of the spearrowhawk which has adapted to hunt for prey on the ground. Like its ancestor, it is a consummate tool builder, constructing wooden spears for the purpose of "fishing" burrowers out of their holes, and has done so for so many millions of years that its beak has evolved a permanently open notch to hold onto tools in this way with the most stable grip. The upland impaler skillfully bypasses getting the sniffler's toxin-covered quills by its mouth at all by skewering them from a safe distance, and then skinning them, snout to vent, with blade-like claws on their inner toe before consuming.

Upland impalers are a very recent arrival to the firmament, less than half a million years separated from a still-extant ancestor species living on the savannahs to the east, the plains impaler, which is a specialized predator of poisonous lumpuses that also require careful handling to make suitable for consumption. The ancestor population reached this region by flying, and plains impalers can still get airborne. With fewer enemies up here, and a new source of prey naive to their tactics, the upland species grew larger - they are now too heavy for their small wings to lift them up. This not a handicap to these birds, for they are fast runners. Much of their diet is comprised of city snifflers, which have had little time to evolve defenses against them - but which are not completely helpless. Though many of their predator-aversion behaviors are instinctive, the city sniffler is also highly intelligent and capable of its own tool use, and some have begun to demonstrate techniques to fight back against their only significant enemy, some of them morbid and yet shockingly clever.

Living in large colonies as they do, city snifflers must regularly deal with corpses of their colonies as individuals die of age or other circumstance. Normally, corpses were taken to latrines and dumped deep below earth, then buried there to keep them away from the healthy members of the colony. Now, though, some city snifflers chuck them out of their tunnels, allowing predators - like the impaler - to find them... after stuffing the dead sniffler's mouth and throat with toxic plants, like the world's least appetizing holiday turkey. The predator skins the carcass as it does any other, but doesn't even think to look inside, and swallows what remains whole... unaware that it has been fed a poisoned bait! The city sniffler has learned to use its own dead as a tool to protect the living. In most cases, the impaler survives after a lot of vomiting, but the experience is so unpleasant that it can go off eating snifflers entirely thereafter. Because impalers are intelligent birds, and young are taught how to hunt by their parents, this can lead to widespread cultural change. Now some impalers are starting to avoid snifflers, even if they have never been poisoned personally, and have switched to other food sources that might be harder to catch, but don't taste quite so spicy. Rarely does any one species maintain a total advantage over another in any situation for long - evolution is a series of competitions, in which one player's winning move is ultimately usurped by another in an endless chain which has been going on, in some form or another, for as long as life has existed here and beyond.

There are other hunters on this plain too, less discriminating in their tastes. These others may not threaten poisonous snifflers, but between them, little else is immune to their hunger. It is so that on the high alpine steppe of the firmament lives one of the world's fiercest, most savage beasts... the wild pug.

A species of repanthor descended from the spireclimber, the wild pug is so named for its pugnacious temperament, though its short, stocky jaw and coloring is not entirely dissimilar to the familiar pet. Though this tribbethere is relatively small at 40 or so pounds, is extremely strong for its size, with both powerful grasping forearms and robust jaws that can deliver a bite as strong as a pitbull's.  This animal's ancestors were alpine-arboreal - that is to say, adapted to live on cementree cliffs, a natural extension of the spireclimber's habits. As the firmament formed over the last ten million years, they spent more time on the expanding summit and gradually became adapted to live on these elevated grasslands. Their fingers - useful to climb - have become shorter, making them better runners, and their heads became larger, mainly to accommodate stronger jaws.

Wild pugs are predators which take down a range of quarry, usually large in relation to their own size. They are ambush hunters that sneak as close to their targets as possible before sprinting in pursuit, and their striped fur provides disruptive camouflage as they stalk. Fowlpaca are common prey, especially juveniles, but adults can also be taken down as the wild pug is a social pack hunter, and this allows them to compete successfully against larger but solitary predators such as the alpine drackal. This foxtrotter has also evolved especially loose skin on its body, making it hard to bite. This provides protection against other animals in fights as well as predation attempts, for it lets the animal turn around in its own hide when bitten and still be able to defend itself. Other animals, even larger and meaner ones, often choose to leave the pug alone after messing with one once, as it is a very difficult animal to kill without sustaining significant injuries yourself.

When hunting, a pack of wild pugs runs up behind the prey and sink their teeth into its flanks to slow it down so that the lead pug can jump onto its back and get a killing bite around its windpipe. The pack structure is varied - it can be comprised of a mated pair and their young or by unrelated animals of a single sex, with very different social structures in each case. There is a much more defined dominance hierarchy in the latter case that is formed by fighting among themselves, in which an alpha individual eats first, and these packs function more like gangs grouped together only for convenience, but lack strong bonds. In family unit packs, by contrast, there is little aggression and the parents work as a team largely equally, allowing their youngest to have first dibs at the meal. In a family pack, the "lead pug" which does the killing bite tends to be the adult male by default as he is usually largest, but this does not mean he is otherwise higher in rank than his mate. Though packs of unrelated adults may initially be more successful hunters than family packs, and can claim larger territories, they work together less effectively and once the first generation of pups born into a family pack are able to start helping hunt, these groups ultimately perform better as they do not spend their time bickering among themselves. Sometimes a third group type may be formed if a breeding pair allow an unrelated adult to join their group as a helper so that they can more effectively feed their pups; this helper is expected to be submissive not only to the pair but also to their young, and so this is a strategy that is only useful to a lonely animal on a temporary basis, as such an animal will never get the opportunity to breed within such a pack, and so eventually leaves once the young have grown.

Wild pugs make their dens underground, usually taking over a portion of a city sniffler territory. Though this arrangement might seem one-sided and harmful to the sniffler, this is not entirely the case as wild pugs are fiercely protective of their dens and so keep away the sniffler's own enemies, especially the varc. The wild pug doesn't pose much threat to the sniffler itself, for it is poisonous, and unlike the varc it doesn't have any interest in raiding its food supply, as the pug doesn't eat insects. The two can thus live relatively harmoniously, one providing shelter for the other, and one providing protection.

There are other foxtrotters here, too. Hopscatches are a widespread genus of grassland foxhoppers that are generally extremely gregarious. They differ from other foxhoppers for their lack of a permanent burrow system and their nomadic lifestyles. Hopscatches are generally tripedal jumping animals, similarly shaped to hares, which can bound at high speeds, during which they may approach a monopedal locomotion for short durations, or move via shorter hops at slow speed. They live in closely-knit clans of ten to thirty, which may link up with other clans and form temporary larger bands of up to 250 animals. These animals do this because their method of finding food is more efficient the more there are working together; they forage by sweeping over the grasslands in a wide line, flushing out all the small prey in an area, that is then quickly caught by the many members in the band. This method of finding food is highly efficient, but the animals don't share their kills; every time something is disturbed, whichever is closest is the one to claim it. They pounce on their prey - a bug, a bird, or a molodont - and catch it between their hands, then quickly shove it in their jaws - the hop-and-catch maneuver for which they are named. Over a long enough time, every member of the clan typically finds plenty of food this way, and finds it more quickly than they would foraging on their own. Only the basic clan structure is stable - the larger foraging bands regularly break up each night as the clans seek separate places to sleep, and reform with other clans they meet the next day. Generally bands have little direct social interaction between each other when cooperating, but young males will use the opportunity when they meet to integrate into new permanent clans if they seek to breed, keeping the groups genetically diverse.

Unlike other foxhoppers, hopscatches don't live in their own burrow systems. They change den sites every day or two, resting in sheltered thickets or in empty burrows in the ground or in insect mounds dug out made by other animals, which they don't typically modify in any way. Their method of feeding requires they always keep moving, as their groups can deplete an area of sufficient food in a short manner of time. Dens are not used even for raising young - pups cling to the backs of adults and are there carried until they are several months of age. Interestingly, the pups' mother does not always do the carrying. Though all females in a band can breed, unlike in other foxhoppers, success is dependent on rank and familial ties, because each female can only hold one offspring and so requires the assistance of numerous helpers to rear her entire litter of four to eight. This means that most surviving young are born to high-ranking females, who can enlist the assistance of grown offspring and of multiple male suitors as their babysitters - the group of helpers is called an entourage, and very popular females can have so many that they do not have to raise any of their own babies. Very low-ranking females, in contrast, may have no help at all. They will be be forced to pick a single pup and abandon the rest of their litters to die. This process still ensures most young are born to the more dominant females in the group, even if they do not actively discourage their subordinates from bearing young as well. Each helper becomes a de-facto parent to their own pup, and once having taken one does not exchange it for another. Doing so provides benefits, even if the pup is not their own relative, as it gives them an ally when the pup grows up, as it will then assist in raising its foster parent's own young as part of their entourage. The more pups it raises earlier in life, the more helpers it in turn has later on. Rank is ultimately defined by how many helpers one has in their entourage, and so it is the oldest, most experienced helpers who eventually become the most successful breeders later in life. In hopscatch social structure there is no way to cheat one's way into a higher rank - it always takes work. Because rank is only maintained in a single clan, and females need it to breed, females stay with their birth clans for life, while only males disperse at adulthood.

Some hopscatches have evolved striking patterns which may serve as disruptive or dazzling camouflage when they are moving in a group. This is most extremely demonstrated in the banded hopscatch of the firmament, which is boldly marked with bright black and yellow vertical bands.  As these animals travel they may stagger themselves in a zigzagging line when foraging, blending together into a jagged wall of stripes that is difficult to discern. If alarmed, they hop closely together in a grouped formation in which their patterns flicker and mix together even more dramatically, making the whole group appear to be a single large animal and making singling out one individual from a distance - or especially from the air - almost impossible. This protects them from predators, the most pressing being flying birds. The banded patterns also hide the vulnerable pups as they cling to adults, their stripes blending together and rendering the young one almost invisible as long as it stays still.

The firmament has been breached by animals from the surrounding landscape several times in the last few million years as its edges eroded, becoming smooth enough to permit the occasional entrance of megafauna even if it was not well-adapted to rock-climbing The establishment of gantuans precedes this second wave of colonists, as their young were always competent climbers - herds of gantuans being able to remaining on the expanded plateau into adulthood, and gradually stripping the trees of their foliage faster than they could recover, ultimately resulted in the death of the living cementrees and led to further erosion. Now, though this sky-high plain is still dominated by its native giraffowl, thorngrazers of several forms are also present. Huge sonorous sirenhorns descend from a more cursorial, bison-like animal of the lowlands. Here, having found their way up the plateau on smoothly eroded pathways just 1.5 million years ago, they have swelled in size to weigh 1,300 pounds. They are now slow-moving, but extremely strong animals which travel the firmament in numbers, grazing the grass and anything else they come across that cannot move out of the way. 

The male sonorous sirenhorn has the heaviest and widest-reaching crest of its genus, which may stretch to 14 feet across and weigh 300 pounds, for it - like all thorngrazer crests - is formed of dense bone. It is the loudest land animal to have lived since the boomsingers died out tens of millions of years ago, using these crests not only for impressive visual display but to reverberate their calls. Males sing to attract mates to their harems, and to deter other males from trying to take them away. The song is low-pitched and extremely resonant, forming a rhythmic pulse near the lower limit of human hearing, which carries for several miles as infrasound through the earth. It is repeated almost incessantly during breeding season. In addition, both sexes emit a wide range of both high and low pitched calls; females - which have only very small sinuses and almost no crest at all - keep contact with their calves with almost comically high-pitched squeals. Only immature sirenhorns have significant predators on the firmament, and may be taken by vultrorcs and large predatory birds. Though mothers are decent at defending their young, they still lose more calves than survive in the first five months, and high infant mortality is the primary population control. Adults are only threatened if weakened by age or illness, though sometimes trip on unseen burrow holes of the city sniffler and other small animals and break a limb, a slow death sentence for any animal of such a weight, let alone one without a fourth leg to spare. The distressed bellow of an injured sirenhorn somewhere out on the plain, which grows more desperate over hours and days, is a dinner bell to all the small predators of the firmament which idly gather to sit around and wait patiently for the fallen giant to die.  

Three miles above the world below, numerous animals make their homes here in Serina's highest elevation biome, and its coldest, too - only here does snow sometimes fall. Most of them descend from sky island animals which were able to climb up the sheer cliffs millions of years ago. Cygnosaurs were the most important colonists, for it was ultimately they which destroyed what was once the largest of all sky islands. For millions of years the agile, climbing young of these creatures sought refuge from enemies - including their own parents - by ascending the cementrees, but they always had to return to ground as they grew too ungainly to remain in their summits. The firmament is the only sky island which became large enough over time to support them into adulthood - for a short while. Over several thousand years, these cygnosaurs marooned on their island in the sky overpopulated their limited habitat, causing widespread deforestation. Eating up the leaves of the trees that grew the sky island, they slowly killed their home. Today the firmanent is a slowly eroding, grassy plateau, the trees that built its underlying, mountainous structure nearly all dead. And without their food source, almost all of those colonizing cygnosaurs are already gone too - but not quite all.

The camelraptor is a dwarf cygnosaur, the only species which has adapted to the rapid change of environment which has occurred over the firmament in the past few million years as its summit was transformed from a vast alpine forest to a grassland. There has not been enough time for the ancestral cygnosaur, closely related to the draconic species, to drastically adapt its anatomy from a large browser.  But there has been just enough time, around three million years, to become far smaller, so that it can "browse" on short montane shrubs. The camelraptor is a neotenic cygnosaur, which has evolved to mature at a juvenile condition - a successful mutation made more likely to have appeared by the huge number of young cygnosaurs produce at a time. It reaches just fifteen feet long, and weighs only 1,600 pounds. It has no bill crest, as most adult cygnosaurs do, with a skull still closely resembling that of an infant of other species. Its tail is very short too, not directly a neotenic trait, but likely a secondary adaptation which makes it harder to be caught by predators as it no longer has size to its advantage to defend itself. To better find sparse food, it has become much more solitary, and now much of its diet is made of up short woody vegetation which it finds in scattered thickets across the plains. Its beak is lined with long needle-like pecten which strip leaves from their twigs, but the tip of its jaw is noticeably hooked, too. This is because the camelraptor is not an herbivore. Like all cygnosaurs, its ancestors were opportunists, but their chicks ate even more animal matter, mostly in the form of insects. The camelraptor is very much like an oversized chick, and so it is the most carnivorous of all gantuans, eating a diet that may be up to 50% flesh.

The camelraptor gets its name from this dual nature. Half the time, it eats coarse vegetation, striding along and browsing with its long neck, vaguely resembling the first of its namesakes. The other half of the time, the camelraptor is an active predator, using those same leaf-stripping teeth to bite other animals. It retains long legs into adulthood and so is a fairly fast runner, reaching almost 40 miles per hour, and has even reduced one of its front toes to a small dewclaw to improve the speed of it stride. It can chase down fowlpacas, and may sometimes be seen charging herds and singling out whichever ones run the slowest, grabbing them in its sharp mouth and violently shaking them to death before tearing into them with its bill hook to open the carcass. More often, though, it favors eating the young of somewhat less speedy animals, such as crested thorngrazers, often searching the tall grass in spring where mothers leave them to hide before they are fast enough to keep up. Like all cygnosaurs, even its own young may sometimes be on the menu, and since it still gives birth to several dozen chicks at a time - just smaller than those of the giant species - this predation may be necessary, lest this species repeat the ways of its ancestors and overrun its island habitat past the ability of the land to sustain it.

Though it is the largest endemic predator, the camelraptor is arguably not the most diabolical. That designation would probably go to the rendrunner... a devilish looking giant skewer, with one of the scariest mouths of any creature.

The rendrunner is a large 'terror bird' evolved from the butcherbeak, endemic to the firmament. Rendrunners are now completely flightless as adults, though like many of the largest metamorph birds they have a volant juvenile life stage and lose flight gradually through the process of ontogeny, and they reached this habitat by flying. The rendrunner is now a lean, long-legged predator of fast-running crested thorngrazers and giraffowl like the fowlpaca, and is able to reach speeds near 40 miles per hour to pursue them in open habitats. Its upper mandible is no longer well-suited to skewer prey - the stresses upon the skull become too strong to do this at such a large scale. Instead, the beak folds in on itself similarly to the claw of a mantis to restrain the neck of the prey animal while the tongue is extended out from the oral cavity to tear out the throat. This organ is now massive and well-muscled, a tooth-covered radula that strips flesh in back and forth grinding motions that transfer small slivers of meat into the mouth with each cycle, and is retracted almost completely into the throat when not feeding.

The largest skewer, rendrunners reach heights of nearly eight feet and can weigh 250 lbs as adults, but like their ancestor they begin life as tiny larvae nurtured by their parents within earthen nests on the plains, and they molt into flying birds at a very small size at a few months of age. Full adulthood is not reached until six years of age, with the youngest yearling birds being strong flyers that rarely land, hawking insects, while adolescents are very similar to the butcherbeak and can both run and fly. Adults are territorial and defend defined home ranges from rivals which would destroy their nests to remove competition with their own young; conflicts are bloody when they occur and so ritualized aggression is more common involving threat displays in which the head is swung backwards quickly so that the jointed end of the beak snaps backward with a loud clatter against the exposed radula. While the marginally smaller females are not as aggressive, males that engage in physical confrontations will often kill each other, trying to get their opponent in a head-lock in their jaws and rend the flesh from its head. Cannibalism is not rare, with winners feeding on those that lose these territorial contests. Adults are not aggressive to younger individuals however, even those unrelated, and scavenging the kills of mature members of their species is important to the survival of adolescents as they transition between feeding behaviors and life stages; both young flying chicks and older ones which are beginning to develop the long legs and weaker flight that herald approaching adulthood will glean scraps of kills made by adults without being harassed. The adult has more to worry about: like a cheetah, it is a fast hunter but relatively weak against competitors, and it often loses its kill to other, stronger animals that share its habitat. 

~~~

Not all creatures of the firmament are devilish - there is one that is quite angelic, and very worthy of its heavenly habitat. The archangels of the Mid-Ultimocene may have been the biggest ever, but the hothouse world has a greater diversity of species overall. Though it is now the carnivores of the group that reign above most others in size, there are as well a range of seraphs that more closely resemble early archangels, with dainty bills, and long arcing necks. These birds are gregarious and migratory; traveling in vast numbers, they are known for their awe-inspiring displays.

Celestial starchasers are descendants of the ptundra ptoose, and are now the crown jewel of a family of elegant, tall crane-like seraphs, which have evolved long, pointed beaks instead of short grazing ones. These birds stand between 7 and 8 feet high and weigh over 140 pounds, and have very wide wingspans of up to 28 feet. They are excellent at maintaining soaring flight, and are among Serina's highest flying birds, readily crossing the world from pole to pole in their travels from one feeding ground to another. They must land to feed, gracefully dropping down from the heavens in open grasslands and marshes, to fill up on a diet of insects, herbs, seeds, and roots. For much of the year, they live in groups of only a dozen or so. The primary social group of the starchaser is a family unit: one bonded pair, and up to twelve adolescent young less than two years of age, who remain with their parents well into young adulthood, learning migration routes by following the constellations in the night sky. But when the time comes to breed, every celestial starchaser on Serina knows to meet at one special place: the nesting grounds, located on the highest summit of the firmament.

Every spring, some 14,000 feet above the world below, tens of thousands of starchasers gather here to breed. But before couples settle down, give birth, and begin to brood their pupating young, they spend several weeks forming and renewing pair bonds with exuberant, synchronized flight displays. It begins with one pair of birds who face together on the ground and begin to clap their bills together and sway their necks in sync, extending colorful dewlaps which are present in both sexes. Soon they are bouncing their heads up and down, calling with whistling melodies, and then leaping lightly into the air. In minutes they are bounding higher and higher, fluttering their wings and rising into the air, and the energy becomes contagious. Others join in; bonded pairs dance to their mates, while young singles just joining the show dance at first on their own until they attract someone's attention. At the peak of the frenzy, thousands of pairs of birds are fluttering into the air and softly gliding down again in perfect matched motion, a choreographed ballet of feathers and the air itself. Then, just as suddenly as it began, the dance is over and the birds split up again to forage for food in smaller groups, rejoining again in a few hours throughout the day. As the breeding season begins, the shows grow smaller as pairs begin to rear young, until all of the birds have found a partner to settle down with.

The starchasers choose the peak of the firmament to give birth as there are fewer predators here than nearly anywhere else; oxygen levels are lower, and few animals live here year-round, meaning that predators are not acclimated to spend long periods of time at such a height. The colder temperatures also inhibit the growth of parasites and reduce disease transmission, important factors while they are gathered in such close company. This lofty nest site has one last benefit to the starchasers too - its height means that when the chicks have hatched and will take their maiden voyage into the air, it is smooth, downward sailing from the summit north to the flooded marshes around the Centralian Sea where the flock gradually breaks up into smaller and smaller groups as each pair rears its young in the food-rich lowlands. Just 50 days after the first of the flocks arrive on the summit, the last chicks have fledged, and the highlands are left quiet once again. Useful for their isolation before the young hatch, they now lack the food needed for the chicks to grow, and so the young ones will not return until they, too, are old enough to begin rearing the next generation of dancers on the roof of the world.