The olm and numerous other cave animals that have become well adjusted to underground life are called troglobionts. Living conditions in caves are different from the ones above ground: the absence of light, modest food supply, constant temperatures, etc. have an important influence on the adjustment of cave animals. These species usually don't have any pigment in their skin, which makes them more or less translucent. Their eyes are vestigial organs; several other senses of these species, however, are extremely heightened, which helps them orientate in the dark and detect their prey. With its well-functioning eyes and pigmented skin, the black olm stands out from other cave animals.