Aristotle and Animals: His Work in Zoology

Aristotle’s work in the field of zoology was exceptionally ahead of its time in many aspects. Aristotle believed that all objects were composed of two things, their matter and their form. He believed that living creatures’ forms were based on an identification process within the soul of the creature. Plants had the lowest form of soul, while animals and humans had higher souls. Through these decisions, Aristotle believed that animals could be classified based on their actions and their forms or bodies. Aristotle’s work remained the basis of biological synthesis for hundreds of years. The dissections Aristotle must have done led to incredibly accurate observations of the anatomies of many animals. Some of his accurate anatomical observations were on the octopus, crustaceans, cuttlefish, and other marine invertebrates. In Aristotle’s History of Animals, he describes the internal organs and forms of 110 animals. Of these 110 animals, it is believed that Aristotle actually dissected forty-nine of them. He is also responsible for recording an accurate description of the embryological development of a chick, separating whales and dolphins from fish, and describing the social organizations of bees, the multi-chambered stomachs of cows, and the birth of live young from sharks. It was centuries before many of Aristotle’s observations were even confirmed because he was so far ahead of his time.

The modern classification system for animals is based on the studies of Aristotle. Overall, Aristotle identified almost 500 different species of animals throughout the process of classifying the animals. Aristotle placed animals with similar characteristics into genera. Once he created these genera, he then went more into detail with each animal’s characteristics placing them into their own species within each genera. Aristotle’s first division was when he separated animals with blood from animals without blood. In this case, an animal without blood meant an animal without red blood. The separation made by Aristotle closely corresponds with the modern separation of vertebrates and invertebrates. Within the animals with blood, Aristotle created five different genera. These five genera were birds, fishes, viviparous quadrupeds, oviparous quadrupeds, and whales. Viviparous quadrupeds are mammals, and oviparous quadrupeds are reptiles and amphibians. The fact that whales are mammals was not known by Aristotle at the time. The animals without blood were separated into five genera as well. These five genera were crustaceans, shelled animals, insects, cephalopods, and zoophytes. Aristotle may have been the first to recognize the similarities and differences of different animals. He recognized the similarities of such things as lungs and blood versus gills and fluid, but he also attempted to understand the differences in the structures of these different creatures. Through Aristotle’s research, he was able to determine that every body part had a specific action or function.