Britannica
Sources used in this answer
How many animal species appeared in Aristotle’s biological writings?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Aristotle
Aristotle, detail of a Roman copy (2nd century bce) of a Greek alabaster portrait bust (c. 325 bce); in the Museo Nazionale Romano, Rome.
In his extensive biological treatises, such as The History of Animals, Aristotle documented and classified more than 500 animal species.1
His research, conducted largely during his time in Assus and on the island of Lesbos, involved remarkably detailed observations of anatomy, diet, habitat, and reproductive systems across a wide variety of organisms, including mammals, reptiles, fish, and insects. While he did not claim to have founded the science of zoology, his systematic approach to taxonomy—which included contrasting animals with blood against those that were bloodless—represented an unprecedented achievement in the history of biology.12