Snarks and the King Trawler

A shoal of shimmering, finger-sized silver fish thousands strong darts along the surface of the sea, the lines between their bodies blurring into a single amorphous blob that reflects and scatters the light pouring upon them from above. A large group of the anchovy-like fish which had gathered to feed on a plankton bloom is being pressed together by a group of larger predator species, and the commotion is already attracting additional opportunists looking for a seafood dinner. Seabirds, drawn in by the splashes as the fish leap from the water to avoid their pursuers, close off escape at the top of the school. Giant ornimorphs with long hooked bills and 30 foot wingspans glide low over the water and skim feed, while primitive seabirds make epic dives deep into the group from the air like gannets, spearing stragglers and swallowing them as they bob back up upon the surface. As the ball tightens, however, many of the predators struggle to single out an individual from the chaotic image, as the fishes continuously change position and remain in tight formation. Mertribs and dolfinches soon hone in on the activity and take turns dashing into the shoals, toothy jaws agape; with luck, they may each catch a single individual by chance, but their predation scarcely affects the shoal's size.

Below the action, a larger form glides leisurely into view from the depths below. It is a massive creature, with a most unusual appearance unlike anything else in the water. Its basic shape is akin to a manta ray, and like one it propels itself upwards toward the surface with slow beats of gigantic wing-like fins that together stretch more than twenty-five feet across. Behind it, a lengthy tail trails in the water and tapers to a wiry whip-shaped tip. It's body is compressed vertically and very wide, the entire front opening into a huge gaping mouth. Just behind the maw, two large stalked eyes swivel left and right independently of the other, fixing a gaze upon the bait ball above. As the creature focuses its pupils dilate and retract rapidly, becoming wide rectangles and horizontal slits. It is a predator like the rest, and it too is hunting. As it rises up toward the feeding frenzy, however, it seems to lose courage. Perhaps unnerved by the large number of other predators taking their turns at the bait ball, it turns its bulky winged form to the side and glides away from the action. Soon, the mysterious monster disappears entirely back into the haze, leaving the other predators alone in their onslaught.

A pack of agile four-flippered dolfinches are now darting into the ball, the most successful of them emerging from the other side with a squirming fish in their long toothy jaws. Groups of mertribs swirl around the outer edges, lunging at any individual which strays from formation, while dozens of seabirds are now hitting the ball like arrows, diving with their wings tucked far back from fifty feet above the water and striking the sea with a palpable crash. The shoal has now packed tightly into a formation known as a bait ball - a spherical formation which provides the greatest amount of protection to the majority of the group sheltered in the interior. And it now that the giant returns.

He appears suddenly from the right, having turned around and now gliding in right along the surface like some enormous undersea bat. On either side of the beasts' maw now project huge net-like structures over ten feet long, supported by a central rod with thin, interwoven baleen spines all down its length which become longer as they reach the tip of the structure. Taking advantage of the work done by the other predators, the beast pushes between them and encloses the bait ball between the two nets. Dozens of fish are snared in his trap and struggle between the tendrils, which contract tightly together and make escape impossible. The ball is now broken; as the other predators swarm to collect the stragglers that avoided the net, the monster retracts his tentacles into the mouth, taking their prey with them. Satiated, he returns to the murky depths, leaving the mertribs, gulls and bumblets to finish their feast.

The predator in question, one of the largest in all Serina's seas in the middle Pangeacene, is surely one of the most unique. He is neither a bird, nor a tribbet, nor any sort of primitive fish. No, his ancestry traces back to the earliest days of Serina, to a wholly different colonist species of a wholly different class. He is the largest of the snarks - a highly derived group of molluscs evolved from the humble pond snail that diversified incredibly in the young Serinan waters and quickly moved out into the seas. He is the current high point of an evolutionary line that began 200 million years ago, from a lineage of large, carnivorous sea snails which fed on smaller invertebrates on the sea bottom.

Snarks

Snarks are the descendants of predatory bottom-feeders which diverged in the Cryocene epoch. The ancestral pond snails were air-breathers, but readily re-developed a gill several times in different lineages from their mantle cavities to respire underwater, allowing them to colonize deep water environments. They developed sharp teeth on their radulas to subdue their prey and burrowed into the sand both to hunt and avoid their own predators. From here a group evolved which hunted as ambush predators; they became dorso-ventrally compressed, with their eyes resting on stalks at the top of their bodies so that they could keep watch for food crawling on the sediment while the rest of their body was hidden. Their shells reduced so that they were no longer able to retract their large, flattened bodies, but they no longer needed to do so as they spent most of their time hidden in the sand. The left and right sides of their foot became flattened and fin-like and by undulating their edges, the snail could now also move quickly over the bottom of the sea bed in the manner of a sting ray, letting them flee from threats or pursue small prey actively in addition to ambush hunting; as their feeding techniques became more active, they became more intelligent, with well-developed brains that would give them an edge in locating and subduing prey. As some species spent more time out of the sand and swimming along the sand, they made use of chromatophores to alter their shades in order to camouflage, as do cephalopods. They were strictly visual hunters, with large eyes and acute eyesight well attuned to both color and movement, and visual signs also became useful for communication with their con-specifics; males developed elaborate, colorful threat and courtship displays, and the ability to switch between them in an instant by altering the chromatophores in their tissues. Species like this, animals which were broadly alike a hybrid of squids and rays, were abundant by the beginning of the Thermocene and spread across Serina's seas, with a few returning to freshwater riverine environments. At the end of the Thermocene, it would be the small representatives of this group that colonized inland habitats which would persist through to the Pangeacene and recolonize the emptied seas.

above: a primitive freshwater snark, similar to the common ancestor of all modern species.

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Snarks diversified substantially after the Thermocene-Pangeacene boundary, responding to the ecological vacuum. In addition to the basal stingray form, some species became better adapted to swim freely and hunt for food in the water column. Each side of their singular foot adapted into a large wing-like fin. The shell became further reduced, covered in soft tissue and soon internalized into a cuttlebone-like rod of calcium that functioned to stiffen the body somewhat like a spinal cord and the body elongated at the rear into a balancing tail. The single gill remained and had now internalized along with the shell. This structure is also now asymmetrical; two spiracles are present just behind the eyes, one of which pulls in water and the other which ejects it after the oxygen has been removed. Water is pulled through negative pressure into an additional internal cavity beneath the left spiracle, causing it to swell against the adjacent gill chamber and push exhausted water up out of the right spiracle. Once emptied, the fresh water is then pulled through a channel into the gill chamber where the oxygen is extracted. There is no connection between the oral cavity and the gill, as there is in fish.

Snarks after the Thermocene-Pangeacene boundary remained mostly carnivores, but their diets broadened from mainly invertebrate prey caught on the sea floor to a wide variety of aquatic animals. More agile free-swimming forms hunted fishes in their element - some even utilized hypnotic color changes to confuse them, allowing them to inch closer until they could grab their prey. All fed with a pair of extensible, jointed radulas, which originated as a pair of sharp spurs on the singular ancestral radula used as a pincer to grab prey in the earliest snarks. In some predatory species these structures can be ejected from the mouth explosively, at extraordinary speed to grab hold of even the quickest prey, while others are content to feed more leisurely on slower prey, such as crabs and other snails, which they pluck off the sea floor; some species specialized on hard-shelled food, with the radulas shortening into a horny beak well suited for crushing which projects permanently from the mouth. And on the opposite hand, other species - including the ancestor of our beast - became filter feeders. Others still became cooperative hunters, utilizing color changes to communicate and coordinate their actions to flush and capture prey and then share the spoils, resulting in further advanced intelligence rivaling that of the higher vertebrate animals.

The beast, actually known as a king trawler, is the largest snark ever to live, with a "wingspan" which can reach thirty feet and a body length of more than forty. Its toothy radulas have specialized into nets of baleen which it can extend and close inward around groups of plankton and small fish and pull into the jaws, where they are swallowed whole. Along with the more commonly spotted lesser trawler, they are extremely nomadic creatures which can cross whole oceans while following plankton blooms. They are most numerous near the cooler polar waters but can be found in any of Serina's seas. They are opportunistic and will take advantage of bait balls induced by the predation of other animals, but most frequently rest on the shallow sea bottom during the day and rise to do their feeding at night, when the plankton rises up to the surface from the depths. While the king trawler is solitary except for incidental gatherings in areas of high food density, the much smaller lesser trawler - which grows around ten feet wide and long - often travels in shoals of several dozen and occasionally more than one hundred. The radula nets of this species are finer, enough that they can collect not only small animals but phytoplankton, allowing for their greater population density and making them the only snark with significant omnivorous inclinations.

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Though their earliest ancestors, the pond snails, were hermaphrodites, snarks are not. Male and female sex organs are born on separate individuals, and sex is determined before birth, though some species are able to change over their lifetime from male to female and this is the norm in one species in particular. Mating is internal and traumatic; the male's sex organ is a projectile spur and to inseminate a female, he injects her in the flank in the vicinity of her ovaries; receptive females normally change color dramatically and develop guide markings on her body when aroused by a male's courtship, which he uses to align his spur to ensure he hits his mark and fertilizes her eggs. The process appears like it would be painful but is in fact pleasant to the female so long as the male strikes the correct area, which is minimally nerved. Stimulation, even penetration by a spur, to this region releases a flood of positive chemicals which function like endorphins in vertebrates, giving a sense of ease and pleasure. That the process is not painful is also demonstrated by the behavior often observed in females of self-stimulation, rubbing their flanks roughly against inanimate objects to stimulate their patches. Overly excited and inexperienced males, however, may attempt to mate outside the designated zones which will invariably result in aggressive reprimand by the intended partner, which may go so far as to remove the male's spur altogether with her jaws. Fortunately for him, it will regrew within a few months' time, by which point he is hopefully inclined to be a bit more careful. Males also utilize their spurs as weapons in combat with each other, except in these instances they aim for more vital areas such as the eyes and face. These are also normally "dry" injections, as releasing sperm in male to male combat would be an obvious waste of his resources. Males lack sensitive mating patches, meaning that they likely do find these injuries painful, particularly in the more sensitive regions.

Like unhappy females, males will attempt to remove one another's spur to prevent their competitors from reproducing, meaning only the largest males in a population will breed - unless they are especially clever. Some males are naturally smaller and flightier than others, less inclined to fight and with lower hormone levels. If a male is obviously not large enough to compete with a dominant male, he will instead adopt a female appearance and behavior, even mimicking a female's arousal markings and submitting to a dominant male's mating attempts and the resulting wound in order to avoid him as a competitor when it matters. He will then sneak in and mate with his partners cryptically, ensuring at least some of their eggs will be his. Different females will prefer either strong and sexy or smart and sneaky partners and make their choices according to their personal preferences, just like humans, which is why both morphotypes persist in many species.

Almost all snarks are characterized by a highly advanced level of parental care, which has been established in the clade since the Thermocene. The eggs are retained until hatching, and the young are born via ovoviviparity, a process which developed in a common ancestor before the snarks diverged. What distinguishes snarks specifically is the level of protection they provide to their young. Almost all species are mouth-brooders and cease to feed for at least a month after their young are born, remaining in vegetated shallows where there is apt to be plentiful tiny prey for the young hunters to tackle and shadowing her brood so that they may retreat to her jaws at the slightest hint of danger. At first her young have a strong shoaling instinct and stay clumped for protection, which allows their mother to herd them, but eventually her young begin to scatter and it is at this time their mother's hunger becomes especially pressing, so that she is forced to abandon them and return to her feeding grounds. Fortunately, by this time her young are normally competent hunters and able to avoid their predators on their own accord. In some species which form pair bonds, the male may guard the young instead of the female, but only the giant trawlers do not provide this level of parental care in some form, instead visiting the vegetated shallows only long enough to release her brood and ensure they reach the safety of cover before returning to deeper water. Their young, which are born as small as cigars, are active predators of the exact same prey they will eat throughout their lives - mostly copepods, shrimp and fish fry - for their first several years, but will catch them one at a time with long pincer-like radulas which do not begin to develop their baleen until they are a foot long.

The king trawler has a lifespan of potentially hundreds of years; though at maturity a female can produce up to one hundred offspring at a time, they do not reach reproductive age until between fifty and seventy five years of age.