The domestication of animals like horses and elephants and their use in warfare necessitated the study of their anatomy and physiology. A survey of Vedic literature has revealed that more than 260 animals were known at that time. Classification of animals and study of their dietary value had been attempted. Human physiology had also been studied. Post-Vedic literature also contains the names of animals and a vast storehouse of observations on their natural history. These observations may have stimulated the later thoughts and concepts about classification, heredity, embryology etc. However, none of the developments in astronomy, mathematics, chemistry, botany and zoology that we have described so far, compare with the tremendous advances made in medicine in that period.