It is possible to view human beings from an ethological perspective if one accepts—as seems undeniable—that man is an animal species who has evolved and whose behavior as well as his biological organs and systems has had adaptive or selective value in that evolution. Human ethologists propose that certain ubiquitous behavioral features or tendencies in man’s life are an intrinsic, relatively unchangeable part of his nature and have arisen and been retained because they contribute positively to his evolutionary success, his survival as a species.