Despite the renewed interest in Aristotle’s Generation of Animals in recent years, the subject matter of GA V, its preferred mode(s) of explanation, and its place in the treatise as a whole remain misunderstood. Scholars focus on GA I-IV, which explain animal generation in terms of efficient-final causation, but dismiss GA V as a mere appendix, thinking it to concern (a) individual, accidental differences among animals, which are (b) purely materially necessitated, and (c) are only tangentially related to the topics (...) discussed in the earlier books. In this paper, we defend an alternative and more integrated account of GA V by closely examining Aristotle’s methodological introduction in GA V.1 778a16-b19 and his teleological explanation of the differences of teeth in GA V.8. We argue for the unity of both GA V and of GA as a whole and present a more nuanced theory of teleological explanation in Aristotle’s biology. (shrink)