Mega-Snarks of the Unbroken Ocean

This guest entry was written and illustrated by Troll Man 

Somewhere along the fringe of the Unbroken Ocean, 280 million years hence. Although this is by far the largest single habitat in the world, stretching for tens of millions of square miles, life here is sparse. Much of the region is nutritionally deficient, leaving it a biotic wasteland; what few animals live here spend their lives constantly on the move, their thin populations spread over thousands of miles as they cross the globe again and again in the search for scattered food sources that appear and disappear as the currents shift and churn. In the vast deep blue, even the largest megafauna are lost in the watery void, so it would be here where the largest animals of the Late Ultimocene call home.

A shoal of large escardines darts through the sunlit surface waters. Reaching up to nine feet long and nearly three-hundred pounds, these, known as ikazuna, are some of the largest of the group. They are fast, pelagic hunters of baitfish and smaller escardine shoals, hunting in coordinated schools with lightning-quick reflexes and spike-like ejectable mandibles. However, there are far, far larger beasts beneath the sea; as the ikazuna reach the continental shelf that roughly divides the shallower depths of the Equinoctial Sea with the vast blue of the Unbroken Ocean, murky shapes gradually emerge from the distance. The crescent shape of immense wings propelling bodies of streamlined flesh the scale of which has no equal in this day and age. These are the largest animals to evolve since the near-extinction of the dolfinches some ten million years ago, but these are much more closely related to the far smaller and fish-like ikazuna than any bird. These are, like them, marine snarks, although they evolved from the devilfish-like shimmershiners rather than the long-tailed ancestors of the escardines. 

Many shimmershiners have grown to truly massive proportions in the hothouse seas; with no real competition for their role as oceanic filter-feeders, they rapidly ballooned to scales matched only by some of the largest marine vertebrates of times long past and far surpassed the largest snarks of ancient times. This species, the celestial shimmershiner, is the largest of them; the very biggest can exceed seventeen metres in wingspan and tip the scales at up to twenty-nine metric tonnes. To fuel such massive bodies, the shimmershiners spend their lives endlessly on the move; adults can travel thousands of kilometres each year following the seasonal and periodic blooms of plankton along the Equinoctial Sea, having to move across the globe to continuously keep up with their nutritional demands. Their lifestyle has changed relatively little in millions of years, and they still rely upon sieving mandibular radula to extract minute food items from the water column. At this scale, this can include shoals of baitfish and small escardines as well, swallowed up all at once in an expanding maw that can stretch over five metres across.

Smaller shimmershiners often dwell in dense schools of several dozen, but social groupings of such size are impossible to sustain at a scale of the celestial shimmershiner. Adults live only in pair bonds, although adolescent animals may live in creches or nestle themselves within the school of a smaller shimmershiner species. Despite their strange appearance, shimmershiners are highly intelligent and their social needs are just as important for survival as dietary ones; pairs may live together for nearly a century and often when one perishes, the other will stop eating, physically deteriorate from stress, and follow within several weeks (either from starvation or predation). This has as much do with practicality as with despair; shimmershiners prefer to pair bond with individuals of similar age, while young, the population density of the species is naturally very low, and a shimmershiner without a partner is extremely vulnerable to predators, so the likelihood of finding a compatible unpaired shimmershiner before dying is extremely low. The increase in size over millions of years was largely induced by pressures of predation, but even at this size there are predators capable of hunting them, and they struggle to get much larger before mortality from starvation and malnutrition stunts the population; there simply is not enough food to support marine filter-feeders larger than this. Living in pairs granted them the ability to protect one another without straining their food supplies by association in great numbers.

The species only breeds once every three or four years, building up their fat reserves to provide for their offspring. Pairs will initiate copulation through a graceful courtship dance, a ritual rarely witnessed by any other living thing due to it only happening in the most remote depths. Females generally release between two and ten offspring at once, which are already nearly four metres in wingspan at birth. Postnatal care is deferred primarily to the male, as most of the female’s energy is used up to produce the offspring, and the father feeds the offspring on the nutritious secretions within his oral secretions, forgoing eating for several days. The young may double in weight within the week, and become independent within a month as their bristle-like radula grow in. Young live in the shallower, more nutrient-rich waters of the Equinoctial Sea, where they can grow more quickly, and they are not as obstructed in their movements through the shallower, more vegetated waters. Adults may breed seldom, and can take over twenty years to reach sexual maturity, but can remain fertile for well over a century. However, ultimately, the majesty of the gargantuan celestial shimmershiners is drawing to a close, and their species is gradually dwindling.

In the history of all life, countless species arise and disappear even without any manner of mass extinction event. In the case of the celestial shimmershiners, they evolved rapidly to refill the niche of enormous filter-feeder which had recently been vacated, and in the early hothouse era, enjoyed a tranquil existence with few competitors or predators, but other marine organisms have since diversified and caught up. The celestial shimmershiners' only recourse was to grow ever larger to outsize competition and predators, but this road has led to a dead end, with the caveat that it breeds seldom and is never numerous, and yet its predators still grow larger and remain capable of hunting them. In the oceans of the future, shimmershiners will still soar beneath the waves in great numbers, but it will be those which have adapted through other mechanisms beyond sheer size, strange new species which must evolve different forms for survival in the strange new times of the late hothouse, but the dance of the magnificent celestials is destined to fade from memory. 

Yet in the end, ultimately, this will be true of all life on Serina, and far from a failure, this is merely an inevitability for all living things large or small. But the chapter of each creature in this long story begins and ends in its own time. As one approaches its resolution, others are only just hitting their climax.

The oceans of the hothouse differ greatly from those of the ice age due to the much warmer climate. Although saltwater now covers a much greater area of the world, much of this is comparatively barren. The warmer waters are far poorer in nutrients than the cool shallow seas of the Mid Ultimocene, and now in most places the seafloor is far too deep for photosynthetic life like algae or marine grasses to take root. Therefore, now large filter-feeders and thalassic grazers must travel great distances to sustain themselves on small pockets of richness in the shallower regions, making continuous migrations of often thousands of kilometres between these regions. And as they traverse the vast blue abyss, they are hunted by a terror that waits for them in the place where there’s nowhere to hide, one older and stranger than anything that has ever ruled the Serinan seas before.

Long gone are the apex dolfinches and burdles that once dominated the oceans; in the waters of the Late Ultimocene, the snarks occupy every trophic level under the waves, including the very highest. With large marine grazers like the shimmershiners and porplets now being plentiful, a predator has evolved to specialize in hunting these oceanic giants. The long, thin mandibles in the calacarnas of old, once perfect for snapping up small fish-like swimmers, have been modified into thick crushing jaws to shear through layers of flesh and splintering bones, the long, flexible body of the early species adapted to weave and dart at shoals of baitfish replaced by a wide, robust one able to withstand grappling with large, thrashing prey. Hunting such large prey, the predators have similarly grown enormous in size; the tyrant calacarna is the pinnacle of this evolution, adults reach between six and eight metres in length and up to five metric tonnes. Under the sea, they are the supreme hunters, with not just size and strength, but great intellect and social cooperation to bring down prey of any size.

Small packs of the calacarnas scour the open ocean for the migratory movements of their prey, their sensitive feelers picking up the very faint scent of prey animals carried miles away in the currents. Like the earlier calacarnas, the tyrant is capable of temporarily raising its own body temperature in preparation for a hunt, but defaults to a lower metabolic level most of the time to conserve energy. Once their target has been located, they coordinate and work together to disable an individual. They attempt to mangle or tear off the flippers of their prey to prevent movement and then rip into their victim with five-foot long mandibles; ramming into the animal at full speed with open jaws is often enough to slice appendages clean off the prey in one swipe. Prey is relatively scarce in the open ocean, but tyrant calacarna can consume over three-hundred pounds of meat at once and, after a substantial meal, go over a month before needing to hunt again; a single successful kill is therefore sufficient to sate a pack for quite a while. The tyrant calacarna, when operating as a pack, can take on prey of any size, even the very largest animals are not exempt.

Most prey tackled are unsurprisingly young, old, or weakened animals, which they pick out over hours or even days of distant observation or minute scent trails. Hunts of the very largest possible prey are rare, but occasionally such a huge potential bounty of flesh presents itself. The most gargantuan shimmershiners are nearly invincible when together, but occasionally they become isolated from one another, such as the recent death of a mate or a young adult not yet partnered up. In these occasions, small packs of calacarnas may unite to bring down prey of such size, communicating from great distances with auditory snaps created by grinding their pharyngeal teeth together, which are picked up through their antennae, and more closely with flashes of colour across their skin, sometimes accumulating to nearly three dozen animals before the hunt begins. Behemoths of such proportions do not die quickly, and calacarnas often work away at them for hours, gnawing away chunks of flesh until the animal eventually perishes of its injuries. Often in such cases, the calacarnas will focus on consuming the more nutritious organ meat within the body cavity and ignore the rest, leaving it for abyssal scavengers as it sinks into the depths, but even this is often more than enough to fill their stomachs.

Although its diet is largely geared toward these occasional migratory hunts of the huge shimmershiners and dolfinches, the tyrant calacarna can certainly hunt other varieties of prey when the opportunity presents itself. Larger, mackerel-like escardines known as ikazuna, mudminnow descendants, sea dragons, and even smaller calacarna species make up a significant secondary portion of their diet, and they may periodically make hunting forays into shallower waters to hunt bottom-dwelling prey, or even pick off land animals which swim between the numerous coastal islands. Prey is crushed and ripped apart with the calacarna’s mandibles, which are powerful enough to pulverize the toughest armour and skeletal pieces, and swallowed in chunks, with bones, shell, and other indigestible parts included (which are usually later regurgitated). This method of consumption is very messy, and the calacarnas are often host to small commensals which snap up the scraps that are inevitably strewn in the water.

Tyrant calacarna packs are generally made up of, or at least originate as, sibling groups due to the oceanic roaming habits of adults; many calacarna species practice parental care, but the tyrants are independent from birth due to the scarcity of prey in the Unbroken Ocean. Adults will migrate to the shallower coastal regions to give birth, and young will live and hunt together in these more productive waters, honing their teamwork and cooperation on smaller, safer prey until they can eventually hunt the largest megafauna of the seas. Some sibling groups may be wiped out by predation, disease, or other factors, leaving the stragglers to seek out other groups, so it is not uncommon for packs to have unrelated members as well. To prevent inbreeding, members of a pack will almost never breed with one another, only copulating with a calacarna from another pack.