Oligocene, approximately 35 million years

In life, Archaeotherium resembled a large, fanged, peccary with bumps projecting from the side of its head. It had high shoulders to carry strong neck muscles to support the heavy head. The brain was tiny, but had relatively large olfactory lobes, suggesting that the animal had a keen sense of smell. It was an aggressive, cow-sized apex predator. Rhino jaws and other mammal bones have been found with bite marks on them that match the large canines of Archaeotherium.