The split between pigs and the rest (mostly ruminants) took place 65 million years ago. The split between ruminants and hippos took place about 60 million years ago. Then the whale lineage split off from the hippo lineage round about 55 million years ago, which gives time for primitive whales such as the semi-aquatic Pakicetus to have evolved by 50 million years ago. Toothed whales and baleen whales parted company much later, around 34 million years ago, around the time when the earliest baleen whale fossils are found.
