Definitions for "Ambulocetus natans"
(meaning "walking whale that swims") is an extinct mammal the size of a sea lion, 10 feet (3 m) long and about 650 pounds. Its limbs allowed it to swim and could also support it on land. It had long, powerful jaws with shark-like teeth, a small brain, and a pelvis fused to its backbone (like land-dwelling mammals but unlike whales). It may have been an ancestor of the whales - it may have evolved from animals like Mesonychid. Ambulocetus was found (in 1993) and named (in 1994) by Hans Thewissen in Pakistan.