Thanatoparous saltipodus

For years, scholars wondered what kept populations of nobbits in the squinch of Koozebane (then known as NEU128) stable. Nobbits are the only large herbivorous mammaloid in the pocket universe and lacked any obvious predators. Although they were occasionally attacked by small predators like the Iridescent Deathneedle, they were not the main prey of any species (a single nobbit feeds an entire swarm of Deathneedles for weeks).

More on nobbits here: http://www.furaffinity.net/view/238...../#cid:17549665

It wasn't until two human observers were stranded in Koozebane for a significant length of time that the true, complex, self-regulating nature of the nobbit lifecylce was observed.

As the nobbit population becomes dense and food scarce, the animals suffer stress. The build-up of stress hormones in their bodies adversely affects their immune system, and they are vulnerable to infection by a fungal parasite known as Mutallosomorphus cryptens. When an affected nobbit reproduces (by planting its head-spike) the fetal animals are drastically changed by the fungus, hatching out from their seed pods not as nobbits but as bugaboos.

Although clearly similar to unaffected nobbits, bugaboos have several striking anatomical differences. They are some 20% larger than normal, with greyish-yellow fur. A bugaboo's single paw is short and broad, heavily padded, letting them hop along with silent footfalls. While nobbits rest and hop upright, like living pogo sticks, bugaboos hold their spines parallel to the ground, the torso counterbalanced by a long, heavy tail which also aids in making sharp turns at high speed, and they rest flat on their stomachs, giving them a low profile. The ears are also shortened to lower their profile.

But where a bugaboo differs most strongly from its parent is the head. They lack the rear eye, the single forward facing eye used mostly for detecting motion. Depth perception is sensed by processing the motion of air currents detected by their whiskers. The nobbit's chisel-shaped teeth develop instead into long, curved sabers set on a short muscular trunk, for the bugaboo is a predator - to be more exact, a cannibal.

The interesting thing about bugaboo predation is that they have the ability to distinguish which of their unaltered prey are related to themselves. Given a choice, a bugaboo will kill completely unrelated nobbits and other bugaboos first, then distant cousins, then half-siblings, and last of all, if no other prey is available, their parents. This behavior is similar to that of the cannibal morph larval form of the earthly tiger salamander.

Unlike the salamanders, which metamorphose into normal adults, bugaboos do not reproduce. With a much higher metabolism than normal nobbits, bugaboos tend to go on brief killing sprees, slaughtering huge numbers of their kin before expiring or being killed by other bugaboos. With their overpopulation problem solved, the next generation of nobbits hatches perfectly normally and the cycle continues.

In fact, this sort of autopredation may be what allowed nobbits to become such a success. Koozebane is an exceedinly small world, and the biomass of nobbits would not be able to support a population of predators large enough to prevent fatal inbreeding. This way predators appear when needed and vanish when not needed.