Although Indohyus, as it is known, looks nothing like the whales of today, it shares certain anatomical features.
Indohyus belongs to an ancient order of mammals that had two or four toes on each foot. Modern day representatives of the group include camels, pigs, and hippopotamuses.
After seeing loose teeth and fragments of jaw bones found by the late Indian geologist A Ranga Rao some 25 years ago, Professor Thewissen obtained rock samples from Rao's private collection. They harboured a treasure trove of complete Indohyus fossils, including skulls and leg bones.
Although the behaviour and habits of Indohyus appear somewhat strange, there is a modern day parallel in the African mousedeer (chevrotain).
The mousedeer lives on land, but is known to leap into the water to avoid predators such as eagles.