The order Cetartiodactyla was created by combining the former Artiodactyla group (pigs, camels, hippopotamuses, ruminants, etc.) with the Cetacea group (whales, dolphins, porpoises, etc.), both of which share a common ancestor. One of the main characteristics of Artiodactyla is that they have an even number of digits (two or four). In these animals, the axis of the hind legs is located between the third and fourth digits. The drawing below shows the limbs of a pig (1), a deer (2) and a camel (3) and illustrates the morphological diversity within this group.
Cetaceans are mammals that lead a permanent aquatic lifestyle. Physical adaptations inherent to this group include the transformation of their forelimbs into flippers and the reduction of their pelvis to a vestigial structure. Despite the significant morphological and ecological differences from Artiodactyla, molecular classification based on DNA sequences reveals that their closest sister group is the hippopotamus.
Within Cetartiodactyla, two groups are specifically represented in our display cases: Suina (pigs and peccaries) and ruminants (giraffes, cattle, goats, deer, etc.). The species belonging to Suina have a snout moved by special muscles. Suina communicate using a wide range of sounds and can be recognised by their sense of smell. They are found in a wide variety of biotopes in a wide variety of climates. Ruminants are characterised by a four-chambered stomach, which allows them to carry out anaerobic fermentation of cellulose thanks to the numerous bacteria living in their digestive system. They engage in rumination, i.e. delayed chewing, which consists of regurgitating food to chew it again. They are animals that walk on the last phalanx of their limbs, which is hoofed. Horns have arisen independently in different families from the frontal bones. These horns are either bony, permanent and covered with skin (as in the giraffe), or surrounded by a horny sheath (in cattle), or renewed every year and covered with skin (in deer).