Related Clues:
- Subjects of Darwinian theory
- Steps in human evolution
- Earth rulers in a 1968 film
- Extras in the opening of '2001: A Space Odyssey'
- Monkeys' uncles?
- Bronx Zoo houseful
- Siamangs, e.g.
- Gorillas and chimps
- Real swingers?
- 'Great' beasts
- Follows suit
- 8-Down and others
- Zoo houseful
- Big galoots
- Forest swingers