Arboreal theory Arboreal theory This theory is proposed by Grafton Elliott-Smith (1912) who was a neuroanatomist who was chiefly concerned with the emergence of the primate brain. The arboreal theory claims that primates evolved from their ancestors by adapting to arboreal life. Primates are thought to have developed several of their traits and habits initially while living in trees. One key component to this argument is that primates relied on sight over smell. They were able to develop a keen sense of depth perception, perhaps because of the constant leaping that was necessary to move about the trees. Primates also developed hands
Animals in Buddhism but by state of mind. This world was called "Tiryagyoni" in Sanskrit, "Tiracchānayoni" in Pāli. Rebirth as an animal was considered to be one of the unhappy rebirths, usually involving more than human suffering. Buddhist commentarial texts depict many sufferings associated with the animal world: even where no human beings are present, they are attacked and eaten by other animals or live in fear of it, they endure extreme changes of environment throughout the year, and they have no security of habitation. Those that live among humans are often slaughtered for their bodies, or taken and forced to work with