The karst species are adapted to live on this limited food supply. A large variety of animals live in caves. Species who spend their entire life in a cave s total darkness must be adapted to the continuous darkness, and usually constant temperatures and high humidity. The adaptations include lack of pigmentation, increased sensory structures, reduced eyes or blindness, low reproductive rates and elongated appendages and antennae. There are degrees of adaptation in cave life.
Adaptation is relatively slight in animals that live in caves for short periods of time.
Biologists classify cave animals based on the animal s degree of adaptation, its cave habitat, and the amount of time it spends in the cave environment. Terrestrial cave dwelling species live on land and have the prefix Troglo . Aquatic cave dwelling species live in the water and have the prefix Stygo . These trogloxenes and strygoxenes spend much of their time above ground. The cave provides a comfortable shelter but the animal must periodically return to the surface for food or to mate.