Ans: The tertiary period is divided into 5 epochs namely palaeocene, Eocene, Oligocene, Miocene, Pliocene. During the tertiary period, mammals diversified rapidly. Some examples were bears, hyenas, insectivores, whales, dolphins, walruses, rabbits, monkeys, apes, lemurs, hippopotamus, hoofed mammals, early mastodons, seals, horses, rhinoceros, rodents, oreodonts, and humans ( Australopithecus).