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Ancient life · Mammals and their kin

Pakicetus

One of the first whales, with four legs.

Our sources give no reliable size for Pakicetus, so this outline of its body shape is not drawn to scale.

When
About 50 to 48 million years ago
Where
In or near estuaries
A museum skeleton of Pakicetus, a slim four-legged animal with a long snout and tail, lit against a dark wall.
A Pakicetus skeleton at the Canadian Museum of Nature. It walked on four legs.Pakicetus attocki skeleton, Canadian museum of nature by Deinocheirus, CC BY-SA 3.0, via Wikimedia Commons. Resized. This version is shared under CC BY-SA 3.0 too.

Pakicetus was a goat-sized, four-legged animal that lived in or near estuaries. It looked nothing like a whale, but scientists recognise it as one of the first cetaceans, the group that includes whales and dolphins.

Within 10 million years its descendants had completely adapted to life in the water.

Pakicetus640 Manow
Pakicetus: 50 to 48 million years ago. That is 1% of the way back to the Earth’s birth.Periods from the ICS chart

Read more in The age of mammals.

Also in mammals and their kin

  • Dimetrodon A sail-backed hunter on our side of the family tree
  • Brasilodon Possibly the oldest mammal, or one of its closest relatives
  • Morganucodon A tiny early mammal named after Glamorgan
  • Dorudon An early whale that lived wholly in the sea
  • Blue whale The largest animal ever to live
  • Woolly mammoth An Ice Age elephant of the far north

Sources