Oceans

The oceans of the late hothouse, 290 million years post-establishment, are less productive on the whole than those of most earlier eras. The tropical global climate means that surface waters are now always warm. This results in a strongly-divided thermocline, in which deep water does not mix readily with that near the surface. As nutrients - dust and soil blown or washed into the ocean from the land, the carcasses of marine life, and other such material - ultimately sink into the depths of the sea, they quickly fall away from surface life, and are effectively locked up out of reach. The open waters of the end-Ultimocene are, in most cases, veritable deserts, in which animals are widely distributed, and food is never abundant. But all of this changes in near-shore environments, thanks to the phenomenon known as coastal upwelling. Strong winds from the land blow down the coasts of the continent, pushing surface waters away from shore. Water from deep below is then pulled up - or upwelled - to the surface, and brings with it nutrients and sediments that, in turn, support the growth of phytoplankton and ultimately allow the formation of complex food webs. While the open seas may appear clear and welcoming, it is the turbulent coasts where the sea truly comes into its own. Along the shores of Serina’s landmasses, animals of all shapes and sizes have adapted to make the most of the favorable conditions to be found below the waves in these narrow edge habitats that abound with biodiversity. 

Welcome to the shore of the equinoctial ocean, along the south coast of Serinarcta. Two species of seademons, the descendants of the pterdevil tribbats, are leaving a nesting site on the great barrier ridge, a massive line of coastal sky islands. They are followed by strange bill-horned unicorn piratrels, an elegant gull-like seabird with a penchant for theft. Down below, guingrebes - large pretenguins - dive to pursue vast shoals of escardine snarks, which fill the niches of baitfish. The snarks also are hunted by other snarks, such as a white-tipped calacarna, a nimble dolphin-like predator that can turn on a dime thanks to its long, narrow flippers.  Nearby on a meadow of sea puffgrass, strange-looking but strongly family-oriented tribbetheres known as sea horses are grazing near the drop-off of the coastal shelf, where water rapidly becomes much deeper. The sea horses, excellent parents, keep their many young corralled and safe from predators such as a pair of marbled whiskerwhales, - fully marine skuorcs - and a juvenile serpentine sea dragon, which may one day grow to become one of the largest of all eelsnakes. A wandering whelican, a giant sea scrounger, and her calf lazily pass by just off the shelf, seining zooplankton such as shrimp and other invertebrates from the water with great gulps of water, which are then expelled and the food seined out. And in the distance, breaching above the waves - perhaps to rid itself of parasites, possibly just for the joy of it - is the apex predator of the seas, the great, awe-inspiring kraviathan, king of all snarks. 

This incredible, bountiful mix of species is all contained within just one region of Serina's oceans. Similar environments can be found on nearly all of its coasts, from pole to pole. And a select few special sites can also be found, nowhere near shore at all, in which specific circumstances allow pockets of biodiversity to form nonetheless. It would be impossible to show every single creature that calls the late hothouse oceans home, even just every large animal, for this biome is simply far too vast. But a wide sampling of global life can be perused - a selection of some of the most interesting species, just to skim the surface. We will start the expedition with those sea creatures that also skim the surface, those which fly over the waves and snatch their prey without completely adopting the water as their world.

Seademons, a varied clade of handstanders, are fish-eating tribbats that are strong fliers, but also capable walkers, which stand on their wings alone, on a single hook-like nail per limb. The tails of these tribbets, unneeded to walk, have become short and sport a wide tail fin, used for steering and braking in the air, but also for added propulsion in the water when they land there to rest or to feed. Though fan-crested seademons, their ears bright red and able to expand outward like flags, are small animals scarcely larger than city pigeons, the awe-inspiring emperor seademon is the biggest handstander with a wingspan of up to fifteen feet. The tallest of all flying tribbats, it is surpassed in weight, a little over 40 lbs, only by some forest-dwelling moonbeasts, and only in exceptional cases. These massive flying tribbetheres are oceanic piscivores that spend most of the year far out at sea, catching fish near the surface and roosting on open water. All seademons have adapted their ears into display structures, and those of the male emperor seademon are dramtically bifurcated to form two antler-like prongs at their distal tip. These structures are entirely ornamental in nature, making the male look even larger and more impressive to potential partners. Each prong is a cartilage rod that can be rotated and swung around in courtship displays, as well as folded back and held out of the way, behind the head, while in flight. Males display on sea cliffs and the ledges of the sky islands, gathering harems of females, but play little role directly in child care beyond defending their territories  - and thus the pups reared there - from most predators, while the females are out foraging for food.

Seademons do not have any specific weight-reducing adaptations compared to other tribbats. Their bones are both solid, thinner but denser than those of related terrestrial tribbetheres like foxtrotters, and they both lack air sacs like birds. The sudden increase of size seen by hothouse tribbats is more related to inheriting a variety of suddenly vacated niches after the ice age than anything else, allowing some representative species to approach the physical limits of tribbat flight that were previously not reached in former ecosystems more heavily dominated by large birds. This means, however, that unlike some birds which can grow to several hundred pounds due to a combination of lightening air sacs throughout their bodies and a quadrupedal launch strategy, tribbats are unlikely to ever grow much larger than these species as they would become too heavy to fly effectively; as is, the seademon is benefited by strong ocean winds on which it soars, and the spook primarily flies only downward to pounce on prey. Though the seademon may appear massive, it is very tall and lanky, with its long arms and neck being most of its height while its abdomen is small and compact.

Emperor seademons, with long pointed wings, can fly nearly effortless over the open ocean on wind currents, and so use very little energy. Like other tribbfishers, their eyes filter out polarized light and so remove glare from the surface, giving them unmatched visual acuity to spot piscine prey even from a great height. This is an adaptation that has served them very well, but it is also one that can be exploited.. by pirates.

Piratrels are several closely related genera of small sea ravens descended from the ice age glacier raven, which are common in marine environments in the hothouse. Diverging early in this period, they are very morphologically primitive birds, changing little throughout the era except in superficial respects, and so demonstrating the timeless success of the basic seabird bodyplan that most sparrowgulls and their ancestors have retained throughout their entire evolutionary history. They are relatives of the larger villaingulls, which they resemble in most respects except for size - all piratrels are small seabirds and weigh less than 4 pounds. Many piratrels share behaviors with their bigger, more belligerent relatives, particularly an inclination to let others do the work in hunting for them and then taking advantage of the spoils, but while villaingulls dominate other species with strength, piratrels must exploit with either their agility or their intellect.

Piratrels as a group are not very charismatic, and many species are quite similar to one another. They tend to be white, with darker wings, and nearly all of them look like seagulls at a glance - expected, as they fill the same sort of niche in the ecosystem. The unicorn piratrel, though, is an outlier. It is a species that is immediately distinct from all others, with males developing a huge, curved crest on their upper bills at maturity that can sometimes reach a length of over 16 inches - almost the length of the bird from nostrils to tail! This crest is entirely for show, an example of runaway sexual selection for ornamentation by the female, which lacks it entirely. Though it is massive, it is delicate and light, meaning that it would be easily broken if males were to fight one another physically, so that like many larger hothouse animals such as loopalopes, conflicts in these birds over mates and for territory are resolved through display with very little harm coming to any individual. This allows these birds a peaceful social structure, which may be especially important, for they nest on the extremely sheer cliffs on the sea-facing side of coastal sky island ranges, where single eggs and chicks must be balanced on ledges just a few inches wide, and any fighting around them could send them tumbling into the sea. By having switched from physical battles to posturing in the male, this ensures safety to nestlings in such breeding colonies, which might otherwise become accidental casualties between fighting males as can happen in some other related species with no display structures and more aggressive temperaments, even when they may nest in less precarious places.

The huge horn of the unicorn piratrel may seem like it would cause issues finding food in the water, but these birds do not have to dive after prey in the sea. They are specialized to follow the tribbfishers - especially the emperor seademon - and follow them to locate concentrated shoals of food - fish or escardine snarks. The little seabirds are almost never seen away from their unwitting hosts, on which they rely to find food, and trail them alone, in pairs, or rarely in small groups, following the far bigger seademons for many miles out to sea. For part of the year they are nomadic, simply flying with their host wherever it goes overseas, but both species become more sedentary during nesting time, when the piratrels center their own breeding colonies in close range to those of the seademons and so can continue to follow them out to sea and then follow them back home again to feed their own young. They are much faster and more agile than them, so will cut ahead and form a feeding frenzy ahead of them when they lead them to a meal. They drop onto the water but don't stop flapping their wings, so as to dance over the surface on their toes, and there they run along quickly and fill their gullets with small fish near the surface, getting the easiest food for the least work.

Unicorn piratrels are also notable for their several color morphs. The most common one is white with pale grey wings, comprising some 60-70% of the population. There is also a stark white form, however, as well as an even rarer dark grey and black variant that may only be seen in 5% of birds in a given population. The reason for the variety may be related to conflicting selective pressures: females prefer contrasted darker markings in males over white ones, but paler birds of either sex are noticed and harassed less by their seademon hosts, for their plumage is less distinct and can be more obscured against a cloudy sky in the frequently foggy, rainy climate of the era. The result is that dark males have greater reproductive success but poorer foraging success, while there is no benefit to dark females at all. The intermediate type, though, has some advantages of both and few disadvantages, which has allowed it to become the most common one seen. Descending from ancestors which began with darker markings, they may now be a relic no longer suited to their niche, and this species may be well on its way to losing this morph of coloration entirely. 

For some animals, like the varied color forms of the unicorn piratrel, it can pay to stand out from the crowd. For others, though, there is safety in blending in with all the rest of your kind.

The sea horses, a group of aquatic tribbetheres descended from the tribbocampus, are widespread herbivores in both inland and marine environments wherever plant growth is abundant enough to sustain them. The largest species is the arctic waterhorse, isolated to the far-northern polar basin. Far more species, however, are oceanic. Coastal beds of marine puffgrasses (which occur on sandy sediment) and kelp-like macroalgae (which grow on rocky coasts) support great numbers of these underwater grazers, but none is more numerous than the golden-mantled sea horse, which can gather in herds numbering in the tens of millions along the vegetated sandy coasts of Serinaustra, all of which - of both sexes - are completely identical. This makes it harder for predators to single out any one individual, and is common for prey species.

The golden-mantled seahorse is a destructive feeder, not only cropping leaves at the sand bed but ripping plants out by the root with its protruding lower jaw, and so groups keep moving as they deplete large stretches of the coast of its vegetation, only returning in many months time when it has had time to regenerate. Yet the sea puffgrasses have adapted to the devastation, even using it to their advantage: the seahorse inevitably eats many of its small, hard seeds, produced on short stems below its foliage, and so passes them out in its droppings on a substrate conveniently cleared of competitors so they may germinate. The seeds are heavier than water, and sink into the sand. If they fell below their parent plants, they would be shaded and die. Many of these plants thus only reproduce sexually successfully after being grazed in this way: without periodic clearing out, they form dense, clonal stands that can eventually choke themselves out, and which lack genetic diversity.  

While they are also aided by sheer numbers to reduce the odds of any single individual being singled out by a predator, golden-mantled seahorses are not absentee parents, but also are proactive protectors and cooperative. These animals live in huge hoards, but each aggregation is in fact composed of many small, bonded family units called pods, which are tied together by female social bonds and guarded by a single male. Daughters and sisters, aunts and cousins all aid their kin to raise their young, which are born in litters as large as six and precocious from day one, but small and very defenseless. When anyone in the group gives birth, they are immediately attended by the others, who look out for danger even as the female is still in the process of birthing, and then aid her calves in reaching the surface for their first breaths of air. As more young are born, they are kept in a communal creche and parented equally by all adults, even those with no calves of their own. This greatly reduces infant mortality, but unfortunately for the young, sea horses breed quickly for such large animals, and when the next year's calves are born, the older ones lose most of the attention. Half-grown females are then expected to help care for the next generation, while males are ejected from the pod by their father and form adolescent bachelor herds with other unrelated males on the outskirts of the herds. The vast numbers of young males being driven to the edges of the herd all at once every year means that they serve as a buffer against predators so that the younger calves and breeding females are safer... not because they protect the herds, but because predators will usually eat them instead of penetrating deeper into the herd to choose another target. This produces a very female-heavy sex ratio, which is ultimately most conducive to the species' survival, as sea horses eat a lot of food and need abundant resources, and only a small number of males are needed to maintain the population, with most ultimately not being able to claim a pod and mate at all anyway. Fewer males surviving to adulthood, and reaching their maximum size at age three, means that not only means the remaining males have to spend less time fighting, but it also means more food is left for the females. Nature is efficient, and for the golden-mantled seahorse, this has meant that most of the male population are considered expendable. Those which survive this rough adolescence, however, will be the strongest and most fit of all, and so most desirable by the females to join their herds and sire their young.

The predators that threaten the sea horse are many and varied. Some, like marbled whiskerwhales, are more opportunistic thieves of the very young calves than anything else. But others, like the largest of all sea dragons, can threaten even the largest adults. 

The late hothouse ocean is a mysterious world, beautiful but dangerous, with exotic habitats home to many animals. At the top of the food chains exist huge predators, among them monsters and sea serpents.

Sea dragons, a clade of large eelsnakes with powerful jaws and relatively large brains, have thrived over the last 20 million years in a climate warm and wet enough for them to spread virtually worldwide over river and sea. Representatives of this lineage can be found ranging from just a few inches in length to longer than a city bus. The biggest species ever to live can be found in Serina's seas during this era, an apex predator that can attain lengths of up to 55 feet. Known as the serpentine sea dragon, this animal's body is heavily elongated and eel-like down most of its length, but the tadpole-like tail of earlier species has become a vertically-oriented, shark-like tail fin to provide faster, more stable movement in open water. Likewise with the increase in its length, a fatty fin has appeared on the animal's underside which improve stability. Too big now to venture fully out of water, the claw-like pectoral fins of this giant serpent have returned to a fully aquatic shape, serving as simple flippers. Prominent operculums over their gills form ear-like protrusions on the sides of these animals' heads, which lend them a vaguely horse-like head shape when the long toothy jaws are closed, coincidentally matching that of some of their prey. These false-ears can be flared outwards in confrontations. 

These large predators mainly hunt vertebrate prey when adult, and though the diet when young is mostly comprised of fishes, snarks and even crustaceans, mature specimens feed almost exclusively upon tetrapod or tripod animals. They are highly nomadic, crossing entire oceans if they so please, but hunt along shore alone or in small groups. Where the sea gives way to sandy or rocky shore, they pursue sea horses as well as solitary burdles and pods of dolfinches against the beach and then corner them. They can nearly beach themselves in pursuit of animals and truly leave them nowhere to run. Because their bodies are so long, relatively thin, but heavily muscled, they have a lot of leverage to push themselves back into the water when they are done, being less likely to trap themselves than other sea animals. 

This sea dragon's preferred hunting grounds are not the open coastlines the sea horse favors, however, but more complex habitats where there is more vegetation and channels of shallow water in which to stalk their prey. Edge habitats as those found within the salt swamp and trilliontree islands, where numerous islands are separated by spans of open water ranging from small channels to distances of several miles, are where they reach their highest population densities. Here land animals must make regular excursions between land areas to reach food resources, seek mates, or find new territories, and the serpentine sea dragon patrols through the shallows in groups just offshore, striking and grabbing anything unwary that tries to cross and collectively pulling it under to drown it. It uses the shallow, murky water to its full advantage, detecting the movement of prey with electric pits in their faces where their ancestors whiskers once were and through the lateral lines that stretch down its length so that it can catch it even without visibility in the muddiest water. Not even the largest land animals are necessarily safe, but neither are little ones. The sea serpent is a versatile hunter, and able to adjust its hunting behavior to specific prey. Where all that is readily available is small, the dragons hunt singly, lying in wait to ambush individuals, even if they try to skip the water hazard altogether by leaping across from tree to tree. With an incredibly powerful tail, the hunter can leap up and snatch small climbing foxtrotters and other arboreal prey in mid-air.

Huge conical teeth line jaws strong enough to crush the skulls of any prey, big or small, and when something is caught the serpent's jaws reflexively snap shut in an instant, like an immense moustrap. It shakes bigger quarry furiously to break it apart, for this hunter's crushing jaws are not built to chew. Once food is ripped and torn into bite-sized mouthfuls, however, smaller pharyngeal jaws break it down inside the serpent's throat. Eating is easier when several serpents feed together, for they can twist and pull the kill apart into smaller portions.

The serpentine sea dragon gives birth in mangrove forests where their young are protected from the dangers of the open sea - dangers which include their own parents. They grow fast in the first five years and leave these nurseries at around a third of their maximum adult length. At this age, adolescents are more strongly social than adults and will always be found in groups, primarily for safety in numbers but also to more effectively take down large prey. Fully grown adults, with no significant threats, spend more time singly and often hunt alone.

To maintain their high metabolic rate, these and many other sea dragons are primarily air-breathers, taking atmospheric oxygen with frequent breaths at the surface and holding air within a long lung within their upper bodies. They retain fully functional gills as well, which allow them to remain motionless and submerged for several hours at a time while resting or waiting in ambush for prey.

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Not every carnivore in the sea hunts big game. Whiskerwhales in general - with some notable freshwater exceptions - are not the fiercest or the strongest hunters. Marbled whiskerwhales, a relatively basal species, mainly feed on small fish and snarks that they catch in active, agile pursuit, and have relatively weak jaws. This is typical for the clade, but just how such small food items are acquired can vary, and out in the ocean, there are some very unusual-looking whiskerwhales indeed.

Whiskerwhales, a group of fully aquatic skuorcs with streamlined dolphin-like profiles, thrive in the hothouse oceans. These strong swimming animals are mostly fish-eaters, with long beaks lined with pseudoteeth. Whiskerwhales have vertical tail flukes capable of strong propulsion and small dorsal fins that help keep them stable at high speeds. True to their name, all species have whiskers along their snouts, used to help detect prey.

Longjaw whiskerwhales are a fairly solitary species, usually found alone or in pairs, native to coastal oceans. Their lower jaw is highly elongated to a sword-like point. Richly innervated, it functions like a finger to let its owner feel for hidden prey in the sand, and is used to skim through loose sediments, detecting buried sea life. When a fish or a snark is detected, the whiskerwhale thrashes its jaws side to side rapidly, knocking it out of hiding and leaving it momentarily stunned in the water column so that the hunter can quickly catch it in its jaws. Though in juveniles teeth line the length of the lower jaw to its very tip, abrasion from feeding over time grinds them down and dulls it in adults into a blunt, rounded rod.

This species is very agile, taking advantage of complex coastal topography to hide from threats behind rocky outcroppings and double back to escape as more ungainly enemies pursue it around obstacles. Though slower than pelagic whiskerwhales, which often have shorter and more compressed bodies, its long, relatively thin shape is well suited to slip through shallow waters where larger carnivores might beach themselves. Longjaw whiskerwhales also use these shallows to their advantage as hunters; they can catch food by herding shoals of fish up to the shore, then swatting them one at a time with its jaw spike which can reach into water just inches deep, truly leaving its victims with nowhere to hide. In this way, keeping its quarry trapped, the predator leisurely picks off the entire school, one fish at a time.

Female longjaw whiskerwhales migrate into vegetated bays to give birth, crossing into secluded inlets during high tide when the water may just barely be as deep as they are tall and where they may beach themselves in their efforts to keep their offspring safe, in which case they will give birth before the tides wash out and strand them, so that their babies can swim the rest of the way to safety. Litters are very large, up to thirty 12-inch-long pups at a time, and juveniles have a long, vertically compressed body shape that lets them slip into seagrass thickets and hide from predators, as well as camouflaging stripes. Their young will be sheltered in these bays from the larger hunters of the sea until they are strong enough to face them. 

And there are many big, fearsome hunters in these seas to face, indeed. 

The seasaw is a huge, fully-aquatic descendant of the swampsaw that has lost all ability to move on land in the last seven million years. A life shaped by water can result in some of the most rapid and extreme morphological changes undergone by any animal, for the selective pressures to swim just a little faster or hold breath a little longer are intense, and it has taken just slightly more than nine million years for the seasaw to evolve. It now averages 15-18 foot long, and can weigh up to 8,000 lbs, with females being bigger than males. Like a hippo, its body is rounded not with fat but with muscle that smooths out its shape in the water, for the seas are tropical except in their darkest depths and so blubber would lend to to overheating. The tail of the ancestral swampsaw now provides propulsion in the water and supports a deeply forked tail fluke formed by its three digits, which have lost all their claws. The forearms of the seasaw however are still well-developed; rather than become rounded flippers as is common in marine life, they are now somewhat flattened so as to lay smoothly against the body when in motion. The claws, now retractable, can be extended as the arms are swept forward to grapple with large prey animals and so give these hunters a significant advantage over fish, marine birds or other sea tribbets who must rely on their heads alone to fight back.  The teeth of the seasaw are similar to its ancestors but now partly obscured by smooth lips for improved hydrodynamics, and are exposed only at the tip of the jaw when the mouth is fully closed. The ears, their orifice no longer open to the outside, are now mobile pectoral fins used to aid in balance in the water. A dorsal hump, vertically flattened, has evolved at the base of the tail as a stabilizing fin.

These sawjaws are coastal ambush hunters, which pursue their prey in small groups like most species. Their jointed hind leg, like those of other past sea tribbetheres such as merwals, is less effective for high speed travel underwater than the tail of an earth dolphin or a shark, so that seasaws are not especially rapid swimmers. Rather than chase quarry long distances in open waters, they are ambush predators that stalk their victims - sea horses especially, but anything they can catch - in coastal seagrass forests or turbulent muddy waters where they can get close before launching their attack. With large eyes and strong senses of smell they frequently feed after dark when their primary prey - large plant-eating porplets - is more vulnerable. Prey is killed with rapid-fire bites to the throat and underbelly by several individuals, causing blood loss and blunt force trauma. But as many porplets defend their own with aggression, it is important that the attack succeeds on the first try. To worry the dolfinches before attacking, seasaws are capable of emitting high-pitched ultrasonic whistles that can damage the hearing of prey at close range and cause them to panic. Adults use quieter but even higher whistles which are above the hearing range of their prey to coordinate their movements so that they effectively can approach their prey in silence.

Seasaw young are born at a large size and high developmental level. They can swim from infancy by necessity, but cannot dive deep or hold their breath for more than a few seconds for weeks after birth. Members of the pack, which are usually related and led by the dominant pair who are parents of the rest, alternately spend time watching the baby at the surface, where it clings to their back and only lets go for short excursions near the adult. Unlike most molodonts, it is born with a full pair of teeth, so that it can bite chunks of meat for itself and does not require mouth-to-mouth feeding. Young just a few hours old will respond ravenously to carcasses dragged back by its relatives from a successful hunt, tearing out chunks of flesh and eating all on their own. Despite this, the period of development is long even for an animal of its size; it depends to some degree or another on its elders for seven years, and is not fully adult until fourteen, which is the earliest it will generally be able to start its own pack and so reproduce. Until then, it will stay around as a helper with its natal group, or else form temporary bands with other adolescents that will occasionally interact with other clans. As it is difficult to form and guard territories in aquatic environments, seasaws are tolerant of others around as long as is food is not scarce, and friendships may exist between animals in different packs, especially juveniles, which meet and play when their respective clans happen to meet up together. Bonds formed early in life may eventually lead to pair-bonds and the formation of new breeding groups as these young ones mature. Within each pack, just one offspring is generally born every four years, with extremely high investment of time and resources going into each one. 

It is not only apex predators, of course, which devote a very long time toward the survival of a small number of young. Such is commonplace among many large animals, even highly dissimilar ones that are not at all close related. And so it is true for the occasional prey of the seasaw, the whelicans, often massive, natatory scroungers that come in many distinct forms.

Long after the ocean age came crashing down, life from the land continues to be drawn back out into the blue. Coastal aquatic environments are often rich in food, especially animal prey, and shore-hunting land predators can gradually evolve to hunt further from land in pursuit of these opportunities. This was the case for the shorescrounger's descent into the marine squelicans, and the processes of adaptation have continued their work upon these birds in the time intervening, rendering them larger and more fully at home beneath the waves. Now known as whelicans, the large, filter-feeding descendants of those early hothouse seabirds join the ranks of whalebirds and great white sealumps as among the most aquatic of non-metamorphic birds.

With their four tentacles interconnected with an expansive net-like arrangement of skin, whelicans filter krill-like crustaceans from the ocean by gulping up mouthfuls of their shoals and filling two huge neck pouches with sea water, and then ejecting it back out through bristle-like protrusions that line the interior of each tentacle deep inside the mouth, that serve to let water pass through, but catch the food and hold it back near the throat to be swallowed or pushed back into the pouches to be stored. Each pouch runs halfway down the animal's body, rising along its length from its throat up almost to its back, and like expandable bags can be used to carry hundreds of pounds of food when parents are foraging for their chicks. These pouches evolved from the throat pouch that served only to collect food in the squelican, but now it has acquired another important purpose: like birdwhales, whelicans are mouth-brooders which incubate their eggs orally, and the behavior evolved in a similar pattern that began with covering the egg with the warm tissue of the open mouth while on land. Primitive whelicans still return to rocky islets to brood their eggs this way, but derived species like wandering whelicans have become fully marine. In these species the female only seeks out relatively protected coastal waters where she can shelter among dense strands of kelp-like vegetation and there spends the six week incubation period, moving little to ensure the eggs remains safe and oxygenated within her pouch, while the male makes forays for up to a week at a time to collect and bring back food first for her and then for their single chick. In doing so he covers hundreds of miles out and across the ocean each time in pursuit of the ever-moving plankton blooms and associated prey, and it is from these wandering movements that the species gets it common name. The pouch brooding system has many similarities to trunko reproduction, but in trunkos the incubation pouch is more specialized - not an extension of the mouth, but a separately evolved orifice below the neck.

Whelican chicks, usually hatched in pairs (one from each brood pouch) emerge from a 20 lb egg weighing about fourteen pounds, and so are extremely vulnerable to oceanic predators, requiring they stay in shallow coastal nurseries under the care of a parent at all times to survive. They are covered in extremely dense plumage that keeps them warm and have a well-developed oil gland at the base of the tail with which they instinctively preen their feathers to provide waterproofing; their feathers are gradually lost over their first year of life as insulating fat takes its place, and the preen gland is vestigial in the featherless adults. Adult females can reach weights of up to 4,000 lbs while males rarely surpass 1,500; this disparity is related to the female's more sedentary nature and need to defend herself and her young from smaller coastal enemies while the male relies on speed and agility to outmaneuver much larger open water predators. It is the male's role to provide food for the female and chick throughout the entire process until it is big enough to follow the adults into deeper water around a year old. It stays with both parents for approximately three years before departing, and adults with older young gather together in large herds for safety from predators. Females, when not with young chicks, are capable of deeper dives than the faster surface-hunting males and so can exploit different food resources; by sharing food with their mate, the two different strategies allow pairs of whelicans to survive in a wider range of habitats and to see through localized food shortages in ways other species without this dimorphism cannot.

Bigger still than the wandering whelican is the sandsifting whelican, also of coastal seas. Reaching a length of 20 feet and a weight of up to 8,000 lbs, these animals are broadly similar to their relative, but are specialized to feed by filtering benthic crustaceans out of sea sediment instead of filtering open water, meaning they can only survive in the shallowest, sandy waters closest to land. They forage by probing their long faces into the substrate and sucking up huge quantities of loose sand into their pouches, and then ejecting it forcefully through a fine sieve of internal hairs that catch the animal prey hiding within. Sandsifters are less gregarious than wandering whelicans and live in family units of a male, female, and several chicks at a time, each of which takes up to five years to reach total independence, but which may be born every year. Both sexes are similarly sized, and as their range is always near-shore, the male does not need to travel far to gather food for his mate and young during the early child-care period as the female remains in thickly vegetated waters where she is safer from predators. While feeding in more open water whelicans are only vulnerable to the largest calacarnas, but can produce an ink-like defensive secretion from their backsides when threatened that can darken the water and allow them to flee in a puff of black fog. 

Whelicans are a young lineage which diverged under ten million years ago, and so living representatives cover a spectrum of forms from semi-aquatic animals that still show resemblance to the ancestral squelican, to completely aquatic animals unable to move on land in any capacity - a range of variation that puts them intermediate to the niches of seals and whales. The smallest have weights measured in hundreds, rather than thousands of pounds. Most of the small species are more basal than the biggest ones, and are able to haul out on land to breed. But, like most things, there is an exception there, too. Striker whelicans are a species of truly pelagic whelican, unable to walk on land, yet they are comparatively minute. And they have among the most restricted ranges of any whelican too, being found only on the Meridian Seamount, a sort of undersea island, a vegetated reef surrounded by open ocean.

Most whelicans are suction feeders, but each species utilizes its throat pouch differently. Some use it to suck up water (and then to eject it as a projectile), others to sieve plankton from the sea, and a fearsome few to rasp chunks of flesh from other large animals. But there are whelicans which have adapted to use these suctioning pouches in even more novel ways. The striker whelican belongs to a lineage of whelicans which have evolved their outer two tentacles into extraordinarily appendages now longer than the rest of their body length combined. Most of its closest relatives are large, pelagic predators. This one, though, is a cryptic, nocturnal hunter of small fish and snarks, and has adapted to hunt its prey as they sleep nestled down within the seagrass beds of the seamount, now a shallow underwater ridge in the middle of the Unbroken Ocean. By day it hides in the seaweed, in water under ten feet deep. It has the remarkable ability to "zip" its two longest tentacles together with interlocking barbs to form a hollow tube between them, through which it is able to breathe a few times an hour by raising them up to the surface and sucking air into its throat pouch, which it then releases into its mouth and takes into its lungs. In this way, it can remain mostly unseen during the day, and avoid its own enemies.

When night falls, though, the striker whelican becomes a deadly hunter in its own right. It cruises slowly just above the grasses, always keeping its eyes - which can focus in all directions, and even in different directions at once - on its surroundings, to watch for larger dangers. It feeds without needing to use its eyesight, by poking and probing its paired tentacles down between the tangled stems. These structures are lined with thousands of tiny pits, each connected to a single hair-like bristle which registers even the tiniest water movements and change of pressure nearby, which signal the presence of a sleeping fish or other prey item. When the tentacles, still held tightly together, come across their victim, a flytrap-like arrangement at their tips opens up and snatches their hapless prey in a set of toothy "jaws" lined with long, hooked spines. Then, with great speed, the whelican expands its throat pouch, producing a pressure vaccum that pulls the fish into its mouth in less than a second to be swallowed. The seawater is then expelled the same way, and the process repeats with each prey item that is captured. The striker whelican's long narrow tentacles extend so far ahead of its body that they function like an independent, much smaller animal that does not disturb the water around it enough to alert the sleeping fishes that it is approaching until it is too late to escape.

Like other pelagic whelicans, the striker whelican is a mouthbrooder, incubating its single egg within its throat pouch, and requiring the cooperation of both the male and female to breed successfully. Because of their unique ability to "snorkel", brooding striker whelicans can hide below shallow water for most of the time they spend incubating their eggs, and so are less vulnerable while doing so.

~~~

Waterhogs, meanwhile, are an order of smaller, more primitive whelicans that have not become completely marine; though they are aquatic, they retain legs that are strong enough to push themselves onto land, and they raise their eggs in rookeries out of the water on isolated beaches. The largest waterhogs thus "only" weigh about 1500 pounds, bigger than the striker, but substantially less than the largest fully aquatic species can reach. 

Named for their generalized diets and boarish tendencies, waterhogs are unique among the whelicans for being omnivores that eat anything they can find including seaweed, fish, crustaceans, molluscs and carrion. A jack of all trades, but a master of none, they can make a living in varied habitats and on anything that comes by. Feeding involves using the tentacles to dig out food from the sand or to tear plant or animal matter into manageable pieces which are then pulled into the throat pouches with a rapid suction of water which is then spat out through bristles along the inside of the mouth, the food kept behind for swallowing. Waterhogs are social, if cantankerous, and usually travel in herds of at least twenty and sometimes several hundred, relying on their numbers for protection from enemies. They have sharp hooks on their tentacles and will use them collectively against predators, mobbing even much bigger enemies before they can single out a target, and males also use them to fight each other for mates so that adult males are often significantly scarred. 

One particular species of waterhog is notorious for an especially ingenious, if gory behavior which it has learned and since passed down culturally for enough generations that it has began to influence their evolution. While very much a generalist like its relatives, it has become a predator in its own right, and though far smaller than the sea's mightiest hunters, it is has adopted a hunting strategy that is among the most wicked. It involves attacking other whelicans and other marine birds such as dolfinches and removing portions of flesh from them while they are still alive. The waterhog order is not typically predatory in this manner, and so other animals have not had much time to evolve to regard them with suspicion. Fanged waterhogs take advantage of this to sneak up on other animals and lunge at them at the last moment, gripping their flanks with its especially long, pointed tentacle hooks and effectively sucking a patch of skin and fat right off their bodies. The violent attack is completed with a fast twisting motion of the waterhog's jaws to tear the cut of meat loose, leaving behind a nasty wound. Larger animals can survive the attack, developing characteristic scar tissue over time, but the fanged waterhog also targets small prey including seabirds and the calves of larger porplets, which are invariably killed in these attacks in which the soft parts of their bodies are effectively pulled clean from their bones by the powerful suction produced by the whelican's mouth and pouch. When feeding on seabirds, the fanged waterhog often pops up beneath them as they float on the surface and sucks them whole into its pouch, repeatedly ejecting them and swallowing them again until the flesh is stripped from the skeleton and then discarding the bones, still articulated with cartilage, to drop to the sea floor.  

There is at least one animal that not even a fanged waterhog will touch, however. A marine herbivore so unpleasant, so prickly, that it is virtually immune to predation - and which can, as a result, dramatically influence its environment.

Productive seaweed meadows grow on coasts with rocky, rather than sandy, substrates in the oceans of the late hothouse, often colored brightly with red macroalgae that takes hold on hard surfaces with sticky holdfasts. This biome is most common in northern waters toward the arctic circle, where such habitats cover thousands of miles of shallow offshore waters. Turbulent and fertilized with strong wave action that brings up deep ocean nutrients, some of these seaweeds grow into veritable underwater jungles over a hundred feet tall, providing habitat for many marine animal species. Fish and invertebrates shelter in the cover the algae provides, while various aquatic and semi-aquatic birds and tribbets feed on both this prey and the plant itself. Elsewhere, such grazing lands are the domain of the sea horses. Yet in the far north, no animal has a bigger appetite for seaweed than one of the smallest and weirdest of all seabirds, the blighter.

A prickly, poky sort of animal no larger than coconut, blighters don't look much like birds. They have blunt snouts, permanently growing beaks that operate like rodent teeth, crab-like pinching forearms, duck-like webbed feet, and a body covered head to toe in sharp spines that render it difficult even to pick up. These oddball creatures are in fact a heavily armored aquatic burdle distantly descended from the seastrider. Over millions of years this much larger shallow-water grazer gave rise to several branches of relatives, some of which developed protective scutes along their bodies for protection from strong-jawed predators such as snarks. Unlike most burdles, seastriders didn't swim with their front legs, which were instead built to prop themselves on and walk along the seafloor. More active descendants therefore swam primarily with their webbed hind feet, using their arms to steer. 

The blighter is not a fast swimmer, for its spiky body means it doesn't have to run from many enemies. It simply toddles along in the water, flapping its hind feet and floating along when it needs to travel. Most of the time, however, it can be found clinging to rocks or the stalks of seaweeds with its claws, gnawing from the top down with its chomping beak. Beginning with the uppermost surface leaves, groups of blighters can mow them down to their roots. Slow metabolism lets this little grazer go up to two hours between breaths, though when actively feeding it will more often surface three or four times an hour, dashing upwards and then down again in just a few seconds. Unlike the seastrider, blighters are neutrally buoyant, able to remain suspended near surface, midwater, or sea floor depending on the needs they have at any one time. These animals are social, moving in herds that provide additional safety from threats, and collectively a large aggregation can obliterate a 50 foot tall seaweed in as little as an hour. Because only a handful of animals are capable hunters of the blighter, it is prone to a boom and bust life cycle in which local populations rise to huge levels, deplete their own food supply, and crash. During boom cycles, blighters can form super-herds of over ten million individuals that strip tens of miles of coastline bare in a single day and become so numerous that their constant diving and surfacing to breathe makes the water appear to be boiling. When all local coastline is mowed down, each individual in the herd enters a migratory phase and disperses in different directions in search of food. By splitting up and heading out to sea in many paths, it is more likely that some smaller subgroups of the super-herd find new feeding grounds, even if most will exhaust themselves far out at sea in their search. As their populations decline and the places they've grazed down are abandoned, seaweed returns over several years and the habitat is restored until the next boom occurs and the cycle repeats. Because these habitats are not constantly available, many pelagic fish which rely on them to lay their eggs and protect their young will only be able to spawn every few years.

Well-fed female bighters are able to reproduce very rapidly by laying clutches of three eggs twice a week, one egg for each of their oviducts which long ago divided into three tubes in their ancestors, the mucks, in the Thermocene. These eggs are deposited just below the high tide line once daily at high tide, and hidden in crevices. They are adhered to the surface with a glue-like substance produced from glands in the oviduct during laying, similarly to some geckos, so that before the tide returns they are adhered in place and safe from most threats. Though mostly safe when submerged, land animals will venture out to try and collect the eggs at low tide, and they are an important food source for many. To acquire enough minerals to allow such heavy egg-laying, female blighters will chew on rocks, reefs, and the shells of molluscs, sometimes eating half a pound, or almost half their own body weight of this calcium-rich material per week.

A proportionally massive air pocket provides the embryo oxygen to survive up to twelve hours underwater daily during high tide, while the hard calcified eggshell is resistant to intrusion of saltwater. Though each gumball-sized egg takes up to six weeks to hatch, so many crowd the sea caves and ledges of the rocky coasts that hundreds hatch each day, allowing populations to swell massively when food is abundant. Babies hatched just over an inch in length can grow to adult size in just four months of constant around the clock feeding. Babies which hatch after the local food that their mothers relied on has been depleted may seemed doomed, but their small size means they are easily transported on currents, and can end up floating away to new pastures with little effort of their own. Indeed, hatchlings transported this way can cross entire oceans, and this species is found across the world, albeit in a patchy range restricted to wherever the seaweed they need to survive is able to grow. Most southern coasts are sandy or silty and vegetated, limiting their presence along equatorial waters to a few scattered regions in the far south and to small populations along islands, most of which never form huge aggregations.

~~~

The blighter may well be the weirdest-looking of the smaller marine birds of the hothouse age. But there is competition. Shellshucks, at a glance, look far more normal. They even have feathers, and they still can fly. But when they open their bills, it becomes all too apparent that even this is not quite the normal bird that it seemed.

Productive coastal oceans continue to draw new creatures from inland seeking food. One of the groups that might thus be expected to colonize the sea is one that has already demonstrated an incredible ability to exploit all manner of food resources over the land across the world, the flickbills. And so with the shellshucks, a genus of diving birds with strange crushing mandibles that feed on molluscs, they can now stake a claim in the waters of the world too.

Shellshucks are large scarreots, a group of parrot-like flickbills much more common in forest habitats. Indeed, this is the only marine scarreot, and one of only a handful of flickbills associated with water. It weighs up to eight pounds, and though most scarreots eat seeds, this one is a predator, more like its daggerbill cousins. Like their ancestors gathered hard-shelled tree nuts and crushed their protective cases in their nutcracker beaks, now the shellshuck does the same with the closest animal thing to a nut: clams, snails, and mussels. With the strongest bill muscles of any scarreot the shimmering shellshuck of Serinaustra's northern coasts shatters seashells, obliterating the muscular attachments that the molluscs use to hold themselves shut and then picking out the meat with their dexterous tongues. The tongue is used to position the clam just right in the beak, but then retracts into the throat when it presses closed so it does not get damaged by mistake. The huge jointed bills of shellshucks fold all the way beneath the upper portion of the beak when closed, and these birds look as if they have a very large lower jaw when they do so - at least until they move it, and the wrong end opens up! Shellshuck ancestors likely discovered that clams and other shellfish were edible by happening upon beds of the molluscs stuck on dry land during low tide near the sea coast, but now the shellshuck is a capable diver in its own right, using its wings to descend up to 75 feet underwater to pry up its food from the sea floor. The only scarreot without zygodactyl feet, shellshucks have moved their outermost toe forward again, where it now connects with the other two with webbing that aids in swimming (the innermost toe still faces backward, helping to grip cliff faces when roosting). Yet the shellshuck is still a scarreot, and as such is a very opportunistic animal with varied feeding behavior. In addition to this diet, it also scavenges carrion, steals the eggs or nestlings of other birds, and occasionally catches fish, especially when they are caught in tide pools during low tide. It feeds very little on plant foods, though, as the types it could easily digest are in short supply near the ocean; just a handful of species of low-growing coastal shrubs which hard bead-like seeds are occasionally foraged, making up less than 5% of the diet.

A moderately sexually dimorphic genus, shellshucks usually share varied white patterns between sexes but differ in the expression of their colored pigments, with males having much brighter and more iridescent plumage than females. These birds are monogamous and despite their derived diets and lifestyles, they breed in a way similar to other species. Lacking trees in which to nest they instead construct burrows near the sea, using their bills like a backhoe to move earth out of their tunnels, and here that their young are raised. Shellshucks cannot lay their eggs in or initially feed their tiny larvae shellfish, as they decompose in a matter of hours in warm weather once killed, becoming a slimy, disgusting mess that is not a suitable medium for their survival. To reproduce, the parents need a larger and more suitable food source, and they must acquire it by finding a larger carcass. A washed-up fish or a chunk of carrion can do the job, but if nothing so easy can be found, they will raid the nest of another weaker seabird species, often a small sea raven, and kill their chick to feed their own. The body is brought back to the nest, where the female shellshuck lays her eggs within it, and this single prey item will nourish her brood for the next two weeks until they are more developed and able to move freely within the nest; while many small eggs are laid, the larvae cannibalize each other as they grow so that just one or two ultimately survives the first few weeks. Both parents then feed the surviving young a variety of food, making trips to forage and returning with additional smaller bird chicks, washed up fish, and molluscs that have already been separated from their shells. The chick fledges in a couple of months almost as large as its parents but more lightly-built, a rare example of a skewer with a condensed childhood and no prolonged juvenile life stage. It takes flight near adult size and stays with the adults several months longer as it learns to forage and open molluscs on its own, with the adult and young not differing in their ecological niches, though the chick has longer flight feathers that let it escape predators more easily than the adults. The adult is a weak flier with only short wings and a greater body weight that makes prolonged flight less convenient, and spends most of its time either floating on the sea or resting near the shore. 

~~~

There are, of course, snails that not even this consummate predator of molluscs can dare partake of. Snarks, after all, are the true rulers of the hothouse oceans, for they include the sea's dominant and most supreme, unchallenged predator, the kraviathan. 

This species was designed, described, and illustrated by Troll Man! 

As the hothouse era has progressed, the seas have gradually become filled with all manner of life once more; trickling down from the coasts, creatures like the aforementioned whelicans, sea horses, burdles, and whiskerwhales have all evolved over millions of years and now join earlier arrivals: pretenguins, sea dragons, and dolfinches among the countless diverse denizens that now populate the salty depths. But in doing so they have entered the dominion of the snails. And among their ranks, they have produced the most terrifying mega-predator in the world, a hunter which surpasses in scale anything that exists or has ever existed on land. Growing up to sixteen metres in length and nearly forty metric tonnes, with a pair of jaws up to three-metres long, this is the largest and most powerful invertebrate to have ever existed, and the largest carnivore to live on Serina during the hothouse era.

An adult kraviathan is the undisputed apex predator of the seas, far exceeding the size of any of its prey. Able to hunt virtually anything by itself, it has largely given up the social lifestyle of its calacarna ancestors, spending most of its life alone and nomadic, as it no longer requires pack-hunting to bring down any prey. This is not to say it has entirely forsaken contact with others of its kind, for it can emit powerful vibrations through the water by grinding its pharyngeal teeth, which are picked up by its fleshy barbels, allowing it to communicate over great distances without ever needing to see one another. Despite its independence from pack-hunting, it remains an intelligent animal that requires occasional social stimulus. Occasionally, kraviathans have been known to work together to hunt especially large groups of prey, working cooperatively to drive the more vulnerable members of a shoal out and then sharing the kill.

A kraviathan, as must be expected for anything of its scale, is a keystone species; its existence has even driven the evolution of formidable anti-predation defences in contemporary animals. Despite its immense strength advantage over its quarry, it nonetheless comes up against fearsome counterattacks and hunts may take weeks to come to fruition. Living in great numbers, many of its prey have evolved to breed fast, live in highly social groups, and defend themselves and one another vigorously, mobbing the much larger carnivore as a single force, and making it hard to pick out a single target. Many kraviathans are covered in cuts and pockmarks from aggressive encounters with prey and failed hunts. The kraviathan in turn has become a superb ambush hunter; its skin can change its hue to match the undulations of the waves, allowing it to become nearly invisible despite its gargantuan size. Once within striking distance, its immense seven-metre fins move in unison to propel the predator forward with powerful acceleration, striking its target head-on, usually killing the prey almost instantaneously. During occasions when the prey can escape the initial strike, the kraviathan may attempt to disorient them by swiping them vibrations from the stroke of its massive flippers.

Kraviathans range throughout the marine environment, but their size means that in contrast to all other species so far seen, they must avoid the shallowest regions of near the continental shelves where reefs and forests of seaweed make it more difficult to navigate - but they regularly lurk just off the edge, waiting to strike on anything that passes too close in its travels. In the most remote corners of the Unbroken Ocean, kraviathans sometimes gather in great numbers to socialize and court one another. The flashing bands of colour that mark their hides in such congregations signal to one another of their peaceful intentions, an important signal for such large, normally solitary hunters. Curiously, they tend to be lifetime monogamous, with females returning to the same males time and again, although they remain apart for nearly all their lives outside of this brief period of courtship and mating. Females give birth to a small number of pups, usually one to three, two most commonly, and care of the offspring is divided evenly between the two parents; if there is one offspring, it will be passed between the two parents every few weeks, but if there are multiple, they will be divided between the two parents. This helps alleviate the stress of caring for their offspring and teaching it to hunt, allowing offspring to learn survival strategies from both or either parents.

Young kraviathans are born already nearly three metres in length and become independent at around six to eight months old. Independent juveniles are much more social than adults, and do make use of the shallows, living in pods in shallower waters of the Equinoctial Ocean or closer to the coasts, mostly hunting smaller shoals of baitfish and escardines similar to smaller calacarnas. Because a full-grown kraviathan has no natural predators and can live for well over a century, they breed seldom and take decades to reach sexual maturity. They may spend over twenty years hunting in the shallows before becoming large enough to venture into offshore waters to hunt much larger prey and take another two decades before first mating. Adolescent kraviathans entering the open ocean are vulnerable, not just to the larger marine predators, but to their future potential prey, such as shimmershiners and dolfinches, which will often take the opportunity to kill the juveniles before they grow large enough to become a threat. Occasionally, some adolescent kraviathans take shelter by allying themselves with packs of smaller calacarna species for a time to help protect themselves against such attacks. Once mature, a kraviathan has virtually nothing to fear and becomes untouchable to practically anything but another kraviathan - a true king of the deep.