A human being born with a tail suffers from atavism.
Recent studies of the progressive mind provide strong evidence for atavism among the more liberal population, although it is not yet clear whether this devolution has found its terminus in its current reptilian form, or if this segment of the population will revert still further to something even more primal; In either case you stock up on water and ammunition.
Rural populist libertarianism is the atavism to Jeffersonian democracy.
--Mr. Big Food
The length of her legs is surely an atavism.
The high-minded Aristotelian licked his empty plate in an act of atavism.