Key Publication: Synopsis of Quadrupeds and Serpents, 1693

Ray’s work, published in 1693, is regarded by some to be the foundation of modern zoology. It was an area in which Ray had less experience, and he did, unusually for him, use an Aristotelian dichotomous system, dividing everything into one of two categories, starting with ‘Sanguinea’ and ‘Exanguia’, roughly corresponding to vertebrates and invertebrates, the former into their method of breathing, i.e. lungs or gills, and so on.

He was also interested in theories that remained controversial in the 1600s, such as whether animals were capable of conscious awareness and intelligence. He specifically rejected the idea of all animals being spontaneously created in the beginning and looked at the problems of how each species evolved. Those theories formed the basis of Charles Darwin’s work on the theory of evolution.