Chapter five looks at other groups of animals that were also present during the Permian that descended from the Synapsids. One group, the Therapsids, would give the world predators and herbivores that are distinguished from other groups of animals by possessing specialized teeth for cutting and chewing. Another group, the Cynodonts, who would become the ancestors of the mammals, also developed a more upright gait, that would let them move more efficiently. It was around this time that evidence for hot-blooded animals can be found in the fossils.