Ambulocetus

Ambulocetus (meaning "walking whale") is a primitive cetacean that originated from Eocene Pakistan, but has since been brought back from extinction into modern Eurasia and North America. It is named as such because it has short limbs and large feet used for swimming. Along with other members of Ambulocetidae, it is a transitional animal species that seems to shows how whales evolved from land-living mammals. While some species of Ambulocetus alive today are semi-aquatic, most species of Ambulocetus are fully aquatic.