Elephant

The earliest known ancestors of modern-day elephants evolved about 60 million years ago. The ancestor of the elephants from 37 million years ago was aquatic and had a similar lifestyle to a hippopotamus.
Social behavior
Elephants live in a structured social order. The social lives of male and female elephants are very different. The females spend their entire lives in tightly knit family groups made up of mothers, daughters, sisters, and aunts. These groups are led by the eldest female, or matriarch. Adult males, on the other hand, live mostly solitary lives.