Artiodactyla (even-toed hoof)

The terrestrial precursor of the cetacean is the same ancestor of artiodactyls (eg. cows, deer and sheep). This common ancestor was a wolf-like creature called Mesonychid condylarth. Mesonychids were completely terrestrial and their eating habits ranged from carnivorous, herbaceous and omnivorous. Their fossils have been found in estuary and lagoonal sediment deposits suggesting they found food plentiful in the water.(Evans, 1987)

Genetic sequencing of mitochondrial b-cytochrome and nuclear material seems to indicate an evolutionary link of modern artiodactyls and cetaceans, although more experimentation must be done. (Adachi & Hasegawa, 1996)

Evolutionary tree of cetaceans' divergent evolution from Artiodactyl mammals. A-Basilosaurus, P-Artiodactyl, M-Mesonychidae, 5-Odontoceti, 6-Mysticeti.(Lockley, 1979)