Cousin Hippopotamus

A post-doctoral researcher at UC Berkeley, Jean-Renaud Boisserie, and two French colleagues have just published a study in the Proceedings of the National Academy of Sciences clarifying the evolutionary relationships of the hippopotamus. This morphological study derives the hippopotamus from an extinct group of artiodactyls (the even-toed ungulates, such as cows, pigs and sheep) called the anthracotheres.

Their study indicates that the closest living relatives of the hippos are not pigs as has been commonly thought, but rather whales, as molecular evidence has also suggested. According to the study, cetaceans and hippos appear to have had a common ancestor 50 or 60 million years ago, and phylogenetically whales can be considered members of the artiodactyls.