Is the hippo going into the sea, or coming on land?

evidence, first from blood proteins, then from molecular systematics, and more recently from the fossil record, show that their closest living relatives are cetaceans – whales, porpoises and the like . Hippopotami have more in common with whales than they do with other artiodactyls (even-toed ungulates), such as pigs. Thus, the common ancestor of hippos and whales existed after the branch-off from ruminants, which occurred after the divergence from the rest of the even-toed ungulates, including pigs. While the whale and hippo are each other's closest living relatives, their lineages split very soon after their divergence from the rest of the even-toed ungulates.