The ancestors of dolphins and whales survived in the seas by shedding ... But this particular repair enzyme does messy work, introducing errors even as it fixes. Other, less mistake-prone enzymes ...

When cetaceans (whales, dolphins, and porpoises ... those that were turned off after cetaceans split from the ancestors of modern hippopotamuses but before toothed whales split from baleen ...

Pathways of evolutionary descent from now extinct ancestors have ... and peccaries; and hippopotamuses. Modern cetaceans don't have toes, but early fossil whales did have even numbered appendages.

Like stripping down to swim, the ancestors ... whales and dolphins with that of other mammals to find 236 genes missing from cetaceans. Of those missing genes, 85 are still present in ...

fully aquatic cetaceans -- the group that includes whales, dolphins, and porpoises -- and semi-aquatic hippopotamuses are each other's closest living relatives and share a common ancestor that ...

Hippopotamuses have ... a closer kinship with modern whales; but that proposition left a troubling 40-million-year gap between the oldest known ancestors of whales (55 million years ago), and ...