Introduction

The biological writings constitute over 25% of the surviving Aristotelian corpus. There are, first of all, the ‘big three’: Parts of Animals, Generation of Animals, History of Animals (usually referred to here by its Latin name, Historia Animalium). These comprise, respectively, some 58, 74, and 146 Bekker pages.

Then there are the smaller works, really monographs or even papers: Progression of Animals (De Incessu Animalium), 10 pages; Motion of Animals (De Motu Animalium), 7 pages; and the essays collected as Parva Naturalia, the ‘little nature studies’, of which the last two are especially ‘biological’: On Length and Shortness of Life, 3 pages; On Youth and Old Age, Life and Death, and Respiration, 13 pages. (Resp. is sometimes treated as a separate work.) Other essays in PN have a clearly biological element, especially On Sleep and Waking, though scholars have tended to treat them only as ‘psychology’, placing them rather with the De Anima than with the biology. De Anima itself is something of a bridge between the biology and the more familiar treatises such as the Metaphysics and the Ethics, and though it certainly belongs with the latter so far as amount of study received is concerned, it was at some point probably intended to provide a theoretical framework for the biological studies.