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The cavemen of the 34th century. (COMIC: Dr. Who's Time Tales)

Cavemen were prehistoric humans who lived in caves.

When burglar Johnny Philpot accidentally activated a time machine, he was transported into the Stone Age near a caveman's dwelling. Just as the caveman was about to strike him with a club, a dinosaur arrived looking for food. Johnny warned the caveman's son to go back, and the two fled while the dinosaur chased Johnny. The caveman later killed the dinosaur with his slingshot, then threatened Johnny with it until he moved off. (COMIC: The Unwilling Traveller)

As observed by Professor Egen, a time traveller come from 1959, most traces of human civilisation had disappeared from the Earth by the first half of the 34th century, with the surviving humans living like cavemen once more. (COMIC: Dr. Who's Time Tales)