Aristotle and Theophrastus as Naturalists: Animals, Plants and How to Sort Them

Tonight we go to the island of Lesbos, where two friends spent their days on the beaches and in the fields: Aristotle with the animals, Theophrastus with the plants.

Fish, octopuses, chickens’ eggs, bees, elephants: more than five hundred kinds of animal. And his friend Theophrastus did the same for plants. They were the first people we know of who tried to sort the whole living world.

Around 345 BCE, Aristotle spent about two years on the island of Lesbos, studying the animals of a great lagoon. With him was Theophrastus, who had been born on the island. Later, in Athens, Aristotle founded his school, the Lyceum, and when he died, Theophrastus became its head.

Aristotle’s books on animals, the History of Animals, Parts of Animals and Generation of Animals, survive. He divided animals into those with blood and those without blood, which is close to our division between animals with a backbone and those without. He sorted them further by how they are born, how they breathe, what they eat and how they live.