cave dweller

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that dwells in a cave, especially a prehistoric human.

from The Century Dictionary.

• noun One who dwells in a cave; a troglodyte; specifically, a member of the prehistoric race of men who dwelt in natural caves, subsisting on shell-fish and wild animals.
• noun pl. [capitalized] A name given to the Bohemian Brethren (which see, under Bohemian), because they hid in caves to escape persecution.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun politically correct Prehistoric human who lived in caves, a caveman or cavewoman
• noun figuratively, pejorative One who behaves like a caveman.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who lives in a cave