The ancestors of orcas, such as these in Alaska, and other dolphins and whales may have jettisoned some genes as these ancient cetaceans went from living on land to life in water. Christopher ...

The ancestors of dolphins and whales survived in the seas by shedding genes involved in sleep, DNA repair and other seemingly critical activities. By Veronique Greenwood When the land-dwelling ...

A 24-million-year-old fossil of a giant tusked dolphin lacks several features common to modern dolphins and baleen whales. The discovery shows that the common ancestor of dolphins and whales ...

Boisserie and his colleagues in the U.S. and Chad say whales and hippos may have shared a common water-loving ancestor that lived 50 million to 60 million years ago.

A new study shows that the similarly smooth, nearly hairless skin of whales and hippopotamuses evolved independently. The work suggests that their last common ancestor was likely a land-dwelling ...

When cetaceans (whales, dolphins, and porpoises) transitioned from life on land to life in the sea about 50 million years ago, 85 genes became inactivated in these species, according to a new study.

In short, whales did not simply decide to hop in the water and ditch their hooves. They evolved slowly, over millions of years, to become the dedicated marine mammals that they are today.

It's long been thought that hippopotamuses share an evolutionary ancestor with whales, but gaps in the fossil record kept scientists from making the connection. In a new study in Nature ...