Ambulocetus natans The most completely known early cetacean (Cetacea), described in 1994 by J. G. M. Thewissen, S. T. Hussain, and M. Arif, from Lower to Middle Eocene beds in Pakistan. It is known by parts from most of the skeleton, showing that it had a long neck, relatively long hind limbs, and five separate (hoofed) digits on each limb. It was the size of a sea lion.

Ambulocetus natans The most completely known early cetacean, described in 1994 by J. G. M. Thewissen, S. T. Hussain, and M. Arif, from Lower to Middle Eocene beds in Pakistan. It is known by parts from most of the skeleton, showing that it had a long neck, relatively long hind limbs, and five separate (hoofed) digits on each limb. It was the size of a sea lion.