They were mammals and looked like large rodents. They were also quite small by whale standards, reaching about four-feet in length. They ate meat, sometimes fish and are the ancestors of whales, porpoises and dolphins.
The only real clue of their connection to our aquatic friends is the shape of their skulls. Pakicetus had a long skull and an ear bone that is unique to whales. Oddly, they also had ankle bones that share characteristics with some of our even-toed mammals. They lived along the shores of a large shallow sea known as the Tethys. Although rare, there are several examples of mammals heading back to a life at sea. Photo: Kevin Guertin from Ottawa, Ontario, Canada - DSCF1201, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=36657302
