The Jackalope and the Goatsucker

No, it isn't the title of a really weird children's fable - it is a life or death battle that goes on in Serinarcta's sky islands between predator and prey, just one of many every day in this exotic, unfamiliar world high above the ground.

A painted jackalope (Cuniculornus fucosus - painted antlered-rabbit) is on a run for its life over the steep and precarious ridges of a sky island somewhere in central Serinarcta. As dusk descends on the mountain, this skyrax - one of the tiniest thorngrazers in the world - has caught the huge eye of a horrifying enemy, the small but deadly goatsucker (Caprexsugus aranecrus - spider-legged goat-sucker.) Neither animal weighs more than four pounds, and their tiny life-or-death conflict goes unnoticed by most residents of the cliff. But even as the fleet-footed hunter seems to gain on its fleeing quarry, crossing the uneven terrain with ease with as many as five clawed limbs to help find a grip while the skyrax has just three narrow hooves to do the same, the goatsucker should not lose focus of its own surroundings. Just as the killer almost touches the fur of its would-be victim, a furious set of fangs vaults out of a stone crevice and latches on the body of the passing predator, which emits a vile shriek as it is pulled backwards, deep inside the cliff. The jackalope runs off unaware of its unwitting rescuer, bounding up and down the almost vertical ridges until it finds shelter in a narrow cave. Left behind, the cliff strikeworm devours its prey, a meal that will sustain it for several days longer than a typical mowerbird catch.

Jackalopes, as skyraxes, are close relatives of skibexes such as unicorns, but at less than 12 inches high are a mere fraction of their size. The males exhibit short backswept horns in bright shades of red, used to attract a mate but not very useful to produce loud calls, as their nostrils open at their base rather than their tips, and they are mostly solid. They graze mosses and short grasses on the steepest edges of the sky islands and can run up vertical rockfaces thanks to their tiny pointed hooves, able to find purchase on tiny footholds in the cliff just half a centimeter wide. Most terrestrial animals cannot find them here, and their main worries are birds - and the strikeworms that, apathetic to their lives, may hunt or help them in equal measure. But the goatsucker too, can navigate this harsh habitat thanks to its light build, long limbs, and many grasping claws. A descendant of the gash-hopper, it is perhaps the most derived of all molodonts: either a quadruped or a pentaped depending on its needs, the three toes of its hind foot have grossly enlarged and the hind leg bones shrunk and fused so that the appendage now seems to come right off the torso like the limbs of a spider. Its semi-sprawling gait, a hold-over from ancestors that climbed trees and later the skin of thorngrazers, means it resembles a bat on the ground. Huge ears and even bigger eyes let this mostly nocturnal hunter find and focus on prey like the skyrax, while its grasshopper-like backwards hind legs - in fact its greatly hypertrophied outer toes - power rapid forward leaps onto the back of its victims. Successfull kills are accomplished with a hug of death from behind in which the neck is strangled with the skeletal fingers of the forelegs, and feeding is done by drinking. 

The goatsucker is physically incapable of opening its mouth, for as a specialized parasite its upper tooth is permanently locked within the hollow, straw-like structure of its lower jaw and can only push forward or retract through this tube, producing suction like a biological syringe as it does so. Carried some point to these islands millions of years ago by passing herds of megafauna whose blood they once sucked, they adapted to hunt whatever they could find, growing larger and becoming active predators. An anti-coagulant protein in their saliva that evolved to keep blood flowing from wounds so it could drink has become much more powerful and is now a digestive enzyme that breaks down tissue into a decomposed, liquidous state that the goatsucker can suck from the carcasses of small prey. This slurry is much more nutritious than blood alone, and now so adapted to feed more efficiently, these large siphontooths no longer bite the herds below. They now live solitary lives on the high cliffs of the sky islands. By day they hide in caves, and here they raise their single young, too. But when the light fades and the island is enveloped in fog, their giant eyes catch the faintest remnants few others can see. They wake to scurry along in the dark like giant spiders and keep all the small and furry things that share their domain on their toes... and in turn, the strikeworm keeps them on theirs.