Anaximander makes a clever guess as to the origin of man. "...he further says that in the beginning man was born from animals of another species, for while other animals quickly find nourishment for themselves, man alone needs a lengthy period of suckling, so that had he been originally as he is now, he could never have survived." He does not explain--a perennial difficulty for evolutionists--how man survived in the transition stage.
Coppleston's History of Philosophy, v. 1, p. 25
(the Contiuum edition, 2003; first published 1946)