The largest surviving work of ancient biology. Across ten books, Aristotle catalogues the anatomy, behaviour, diet, and reproduction of hundreds of animal species — from sea urchins to elephants — with an empirical rigour that would not be matched for two millennia.
Start ReadingAn overview of animal classification. Aristotle establishes the basic framework for comparing animals — by their parts, activities, modes of life, and characters — and surveys the external and internal parts of blooded animals.
The parts of viviparous animals. Aristotle examines the internal organs, reproductive systems, and skeletal structures of mammals, providing detailed descriptions based on his own dissections and observations.
The reproductive organs and systems of fish, birds, serpents, and other animals. Aristotle traces the remarkable variety of reproductive structures across the animal kingdom.
Bloodless animals — crustaceans, cephalopods, insects, and testaceans. Aristotle describes the anatomy and habits of invertebrates with impressive observational detail.
Reproduction across the animal kingdom. Aristotle examines how different species reproduce — spontaneous generation in insects, viviparity in mammals, oviparity in birds and fish — and catalogues their breeding seasons and habits.
Bird and fish reproduction in detail. Aristotle describes nesting, incubation, egg development, and spawning behaviour across dozens of species.
Human reproduction, growth, and diseases. Aristotle examines puberty, conception, pregnancy, and childbirth, then surveys common human ailments and their causes.
Animal characters and intelligence. Aristotle observes that animals display traces of psychological qualities found in humans — courage, timidity, gentleness, cunning — differing in degree rather than kind.
Animal habits, feeding, and migration. Aristotle catalogues the seasonal behaviours, diets, and movements of birds, fish, and land animals, drawing on reports from hunters, fishermen, and travellers.
Causes of sterility and fertility. This final book, whose authenticity has been questioned, examines the factors that affect reproductive success in animals and humans.