Earth bear
The earth bear is a subterranean creature native to Metcitum, where these creatures abound beneath the surface of the world. Despite the name, it is not actually a bear, or even a mammal, though its ambling gait does somewhat resemble a bear's. Earth bears are remarkably resilient creatures, able to withstand extreme temperatures and high pressures and go for long periods without food or water.
Description
Earth bears are ungainly-looking creatures about three meters long with pudgy bodies like stubby caterpillars, supported by four pairs of stumpy legs. Each leg is tipped by eight large claws, which they use to burrow through the soil and can use to defend themselves quite adequately if threatened. They have no tails; an earth bear's body just ends at their back pair of legs. A number of whiskerlike bristles sprout from various locations on the creature's body, augmenting its tactile sensations. The earth bear's tough skin is brightly colored, the colors varying between species and often even within a species.
An earth bear's head bears some superficial resemblance to that of an obese walrus, with two frontally located compound eyes. Its mouth, however, is circular, not entirely unlike a lamprey's, though with the folds of flesh that hide it this isn't necessarily obvious when it's not in use.
Anatomy
Earth bears have no skeletons, per se; they are essentially sacs filled with fluid, threaded through by numerous vessels that serve to ease the movement of essential chemicals and nutrients through its body. In contrast to vertebrates, the earth bear's main nerve cord runs across its ventral surface, dotted with several ganglia along the way. The earth bear has a fairly standard digestive system, but a very unusual respiratory system; pores scattered all over its body lead into pulmonary vesicles that essentially act as numerous miniature lungs.
Habitat
Earth bears thrive particularly in moist environments, and are especially common near the Caloski Swamp. However, these adaptable beasts can live in an enormous range of environments, and are even found beneath such arid environments as the Dry Forest and the Valley of the Skulls. In any case, earth bears generally spend their entire lives deep underground. While they're fairly common all over Metcitum, people there who have spent their whole lives aboveground are never likely to have seen them.
These creatures, however, can survive a startling range of environmental extremes. They can shrug off being frozen to extremely cold temperatures, heated far above boiling, exposed to tremendous amounts of radiation, and many other situations that would quickly kill a human. If necessary, they can place themselves into suspended animation, reviving only when conditions are favorable to their survival. No part of the earth bear's extraordinary hardihood is magical in origin; as phenomenal as their abilities of survival are, they seem to be entirely biological.
Diet and behavior
The earth bear feeds on the body fluids of other organisms, which they extract by piercing their prey with hard mouthparts called stylets, and then sucking it out from the resulting wound. Earth bears are not particular about what they dine on, and consume the sap of trees as willingly as the blood of animals. However, in their subterranean environment, trees and other fluid-filled plants are relatively hard to come by, and earth bears are likely to subsist mostly on blood. A favorite prey is the soilworm, due to its large size and sluggish motion, but there have been many reports of earth bear attacks on humans.
Earth bears are very slow-moving, and therefore do not pose much of a threat to humans with unrestricted movement. Those who are immobilized or buried, however, can find themselves easy pickings for these thirsty creatures, and an earth bear is large enough that it can easily drain enough blood to kill a human. Graveyards in Metcitum are often constructed with metal bars underground to prevent earth bears from wandering in and sucking the blood out of the corpses.