Littoral Nightbiter

The nightbiter was a small dividopteran tribbat that specialized earlier in the Ultimocene as a flesh-biting parasite of boomsingers, evolving a cookie cutter jaw to scoop mouthfuls of flesh from their huge, unwitting hosts.

Though boomsingers died out some 5 million years ago near the start of the current ice age, their bane eked out survival even in their absence by turning their attentions to the growing herds of thorngrazers, albeit in reduced numbers. Though thorngrazers were individually far smaller than the prey they first evolved to go after, they made up for it in their larger populations.

As the climate worsened over time and pushed the thorngrazers upon Serinarcta ever-nearer to the southern coast, the nightbiter became more opportunistic. Seasonal seabird colonies near the coast eventually became the primary focus of one population for part of the year. Though at first they still only took single bites, this smaller prey was killed in the process, and the scent of the dying bird chicks would attract other nightbiters which would choose to feed from the same carcass for protection in numbers from their own predators. Such forms were the ancestors of the littoral nightbiter, a late ocean age species which could be described as a sort of flying piranha.

Littoral nightbiters are still nocturnal predators, using their large eyes and acute vision to navigate but a strong sense of smell to locate their prey. They are much more actively predatory rather than parasitic now, and have grown significantly larger, about 8 inches tall and half a pound, adaptations to better maintain warmth. They are strong and now almost silent flyers with insulated, hair-covered wing membranes and forked tail membranes that improve their maneuverability in the air, and they can travel long distances in a night to find food sources that vary seasonally. Spring and summer seasons are spent along both the north and south coasts of the seaway, including on glaciers, where they hunt bird chicks, especially pretenguins, and young sea-molodonts, while in the winter they are highly migratory and spend most of their time around the open sea. There they regularly feed in a way more like their ancestor species, by biting chunks out of the backs of floating bloats as well as by scavenging daydreamer/gravedigger refuse.

These nightbiters have become much more social than their predecessors, and rely on mobbing to kill their victims when hunting, collectively overwhelming animals that cannot escape them with many massive bites all at once. Lurking along the edges of nesting colonies, they target weak, sick, injured or abandoned young animals and once having chosen a target attack it in swarms. Once one begins nipping, and has determined a chosen animal is not able to fight back or flee, the scent of blood is picked up and in minutes as many as one hundred can have closed in and begun to tear into the prey. They feed quickly and in ravenous bites, leaving it skeletonized in a short period if not driven away by larger scavengers or another intervening animal. Though they are very flighty and timid alone, they gain confidence in groups and can even occasionally attack gravediggers as they sleep, though this would be very rare given the availability of easier food sources.

Virtually all floating bloats’ backs are covered in numerous small round scars showing past nightbiter attacks, but they are so large the small wounds quickly heal over with little long-term health issue. Eventually their backs can become so covered in thick scar tissue that they are hard to bite into, so that primarily it is the young which are targeted. As nightbiters need solid places to roost, their forays into the open ocean are limited to distances they can reach within a day's time from a nearby island, where they huddle up in cracks between rocks for the day. If on sea ice as many spend their summers on the southern ice shelf, they gnaw a small burrow in which to hide using their large lower teeth. Exceptions would be during migration between the open sea and the coasts, during which they may fly for a couple days at a time, relying on fat stores before finding a new place to rest.

Gravediggers are usually indifferent to the littoral nightbiter, which is unlikely to harm anyone unless they are alone and gravely injured. However, they occasionally use their large, serrated lower teeth as simple carving knives, catching them by applying a sticky glue made from rendered bones to the backs of bloats so that the small creatures coming to feed become stuck.