troglodyte (n.)

"cave-dweller," 1550s, from Middle French troglodyte and directly from Latin troglodytae (plural), from Greek troglodytes "cave-dweller, cave-man" (in reference to tribes identified as living in various places by ancient writers; by Herodotus on the African coast of the Red Sea), literally "one who creeps into holes," from trogle "hole, mouse-hole" (from trogein "to gnaw, nibble, munch;" see trout) + dyein "go in, dive in" (see ecdysiast). Related: Troglodytic.