Troglobite

Part of speech: noun

Definitions

1. An organism that spends its entire life underground in caves and cannot survive outside this environment
2. A creature adapted to live exclusively in cave systems, dependent on subterranean conditions for survival
3. An animal that inhabits caves permanently and relies on cave ecosystems rather than the surface world

Etymology: Cave-dwelling animals are a striking case of life adapted to total darkness, and "troglobite" names the most extreme of them: an organism that lives its entire life underground. The word is built from two ancient Greek elements. "Trōglē" meant "hole" or "cave," and "bios" meant "life," so the literal sense is something like "cave-life." The German "Troglobie" came first, and English took the term from it. The ending "-ite" is the common scientific suffix for something belonging to a category, as in "Israelite" or "dynamite"-style coinages, and in biology it marks an animal's ecological type. Its partners are "troglophile," for creatures that can live in caves but also outside them, and "trogloxene," for visitors that enter caves only briefly. Together these three words sort cave fauna by how deeply they depend on caves.