Pakicetus, the first whale
A wolf-sized land animal with a whale's ear runs beside rivers in Pakistan.
- When
- —
- Duration
- 2 million years
- Known to
- ± 1 million years
- Era
- Eocene, Cenozoic
Pakicetus is classified as a cetacean on the basis of its skull — particularly the involucrum and the arrangement of the middle ear — but it is a four-legged runner that would have looked like nothing so much as a long-snouted dog. It lived beside shallow streams in what is now Pakistan and probably hunted in them. Its discovery reframed the whale origin story: the transition begins not with a swimmer but with a terrestrial predator whose hearing was already changing.