I was today-years-old when I learned that a whale’s closest living relative in the animal kingdom is a hippo. While they are not direct descendants of one another, their family trees are strikingly similar.
Pakicetus lived over 50 million years ago in the area we now know as Pakistan. They were purported to be roughly the size of a wolf (or a goat), were meat-eaters, and straddled the world of land animals and water creatures. After being discovered in 1983, resin casts of the Pakicetus’ skull showed it had much more in common with modern-day whales than previously thought.
The Pakicetus fossil shows a head that is distinctively elongated, just like a whale. They also have ear holes that closely resemble that of modern-day whales. The American Museum of Natural History shares:
Though rare, mammal species adapting to life in the sea has happened at least seven times in different major groups of mammals. Still, this reverse pattern accounts for some 100 living mammal species that inhabit the oceans today, from three major groups.
AMNH
After Pakicetus, evolution jumps us to an animal called Ambulocetus — their feet more closely resembled flippers and probably pulled themselves along the ground like modern-day seals. Then from Ambulocetus we move to Dorudon and it is here that we have an animal that now completely lives in the water. The evolutionary process from Pakicetus to Dorudon is a measly 10 million years, which is nothing when you think of how long it takes for most evolutionary events to take place.
Check out the amazing evolution of Pakicetus to modern-day whales below and let us know what you think!