History of Animals, Volume IIIn History of Animals, Aristotle analyzes "differences" in parts, activities, modes of life, and character across the animal kingdom, in preparation for establishing their causes, which are the concern of his other zoological works. Over 500 species of animals are considered: shellfish, insects, birds, fish, reptiles, amphibians, and mammals including human beings. In Books IIV, Aristotle gives a comparative survey of internal and external body parts,