The Sea Dragon

Eelsnakes, a group of anguilliform swordtails which evolved very early in Serina’s history, have survived more than two hundreds million years with only modest alterations to a body shape and behavior patterns they perfected early on. While a few groups of these carnivorous, air-breathing fishes abandoned the water completely over their history, such as the fangworms, most of them have remained only semi-terrestrial, able to haul themselves over land when necessary with synchronous movements of their specialized and leg-like pectoral fins, but living primarily in water and retaining gills to respire beneath the surface.

Convergent evolution upon a consistent, ancient body shape has resulted in eelsnake clades repeating the evolutionary adaptations of earlier relatives several times, but perhaps no less dramatically in the repeated evolution of large eelsnakes into crocodile-like ambush predators. With their weight largely supported by the liquid medium in which they live, eelsnakes easily increase in size, and their combination of aquatic respiration with the ability to move over land and breathe atmospheric air for short periods renders them very capable of colonizing isolated, inland water source as well as to cross oceans to reach island habitats. On the Meridian Islands lives the platyconda, a large and snake-like ambush predator of terrestrial prey while upon Serinaustra another clade, once very successful, had evolved to swim up the cold rivers that emptied into the sea and hunt grazing animals living upon the southern steppe. More specialized to this particular niche, during the late Pangeacene and early Ultimocene they thrived on this southern landmass, lurking in rivers and lakes and evolving massive, crushing jaws to pull thirsty land animals underwater and drown them. Though they grew to lengths of up to twenty feet and could weigh half a ton, they were in fact closely related to the fangworms, a group that still survives today but which lacks any megafaunal members.

When the middle Ultimocene ice age locked the southern continent under ice and snow, most of these large carnivorous eelsnakes went extinct, as they nestled deep into the sediment of the inland lakes and went into a hibernation from which they were never awoken when spring no longer came. Only one species is still extant during the ocean age, one which was noteworthy for its seasonal behavioral changes. While their relatives went dormant through the winter, this species was active the year round, moving from freshwater out into the ocean with the onset of winter and so avoiding the deep freeze. At sea they adjusted their behavior toward a more active, hunting lifestyle, using fleshy barbels on their faces to dig out burrowing fishes from shallow coastal sediments and using their remarkably long, flexible necks and narrow snouts to reach in and snatch hiding prey from holes in snail reefs. Their more nomadic lifestyle allowed them to migrate north, where they found land still warm enough at least seasonally to travel upriver, and new prey to hunt there. Today the migratory sea dragon is the only living species of its once diverse group, but the ocean age has been kind to it, allowing it to spread nearly worldwide across remaining thawed water anywhere it can be found. The sea dragon, which grows to fifteen feet in length, is most frequently seen in summer up to four hundred miles inland, where it dwells in rivers of glacial meltwater and attacks trunkos, circuagodonts and even young thorngrazers as they attempt to cross or come to drink. When winter’s chill returns they migrate south in large numbers into the ocean, where they spend the next few months lurking in thickets of sea bamboo and other water plants and catching anything that comes too close.

Though the sea dragon is basically aquatic, they utilize basking to heat their bodies above ambient temperature whenever possible and can often be seen gathered on beaches and offshore islands in groups on sunny days. This allows them to be more active than many other ectothermic predators that are unable to leave the water in this way as well as to more quickly digest their food.

Among the aquatic fishes, the sea dragon is relatively intelligent, with a large brain that is adapted for a surprisingly complex social structure and capable of considerable problem solving. Females care for their precocial offspring for several months, allowing them to follow them around for shelter and to feed from their kills, and even chasing away potential predators. Adults are capable of cooperative hunting both among one another and - more interestingly - with other animal species both aquatic and terrestrial to capture prey. Groups of sea dragons have been observed to enlist dolfinches, including daydreamers, to chase large prey into their waiting ambush, with the sea dragons restraining the prey and the dolfinches then killing it. Both predators then amicably share the spoils.

above: a sea dragon pursues a juvenile sharkbird along a rocky coast.

(guest illustration by Bombynx)