Troglodyte
/ˈtɹɒɡlədaɪt/
noun
A member of a supposed prehistoric race that lived in caves or holes, a caveman.
(by extension) Anything that lives underground.
“The cave was populated by albino scorpions, blind salamanders, and other troglodytes.”
A reclusive, reactionary or out-of-date person, especially if brutish.