Ambulocetus was an early cetacean that could walk as well as swim. It is a transitional fossil that shows how whales evolved from land-living mammals. Its name means 'walking whale'.

Ambulocetus looked like a three-metre long mammalian crocodile. It was clearly amphibious, as its back legs are better adapted for swimming than for walking on land, and it probably swam by undulating its back vertically, as otters, seals and whales do. It has been speculated that Ambulocetids hunted like crocodiles, lurking in the shallows to snatch unsuspecting prey. Chemical analysis of its teeth shows that it was able to move between salt and fresh water.

The reason scientists consider Ambulocetus to be an early whale is that it shares underwater adaptations with them: it had an adaptation in the nose that enabled it to swallow underwater, and it shared ear structure with whales, enabling it to hear well underwater. In addition, its teeth are similar to those of cetaceans.

The Ambulocetus fossils were found in Pakistan. When the animal was alive, Pakistan was a coastal region bordering the ancient Tethys Sea.

See also

• Evolution of cetaceans

External links

• Whale Origins
• BBC Online