The word for today is…
troglodyte (noun) – 1. (a) A member of a fabulous or prehistoric race of people that lived in caves, dens, or holes.
(b) A person considered to be reclusive, reactionary, out of date, or brutish.
2. (a) A nonhuman ape. Not in scientific use.
(b) An animal that lives underground, as an ant or a worm. Not in scientific use.
Source : The Free Dictionary
Etymology : “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;”) + dyein “go in, dive in”.