ABSTRACT
The artiodactyls are an old group, dating from the Eocene, but their definitive ascendance began in the Pliocene and continues today. Since the Pliocene the even-toed ungulates have gradually been crowding out the odd-toed ungulates and the great majority of those still living belong to the order Artiodactyla. Pigs were probably present throughout the Pleistocene in Europe, although only one species existed at a time. The pigs are omnivorous and their diet, like their dentition, resembles that of the bears. The hippopotamus appeared in Europe at the end of the Villafranchian and made repeated incursions in later interglacial faunas; in Italy it seems to have been present throughout the Pleistocene. The deer have evolved from a group of Miocene ruminants, the Palaeomerycidae; the same group apparently also gave rise to other higher artiodactyls including the giraffes, which are the closest living relatives of the deer. The bovids evolved in the Miocene; their closest relatives are the American pronghorns.
