Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Terrestrial, or Tetrapod, Vertebrates — Amniotes
Class Mammalia — Subclass Theria — Suborder Non-ruminantia

Non-ruminants comprise a small group of artiodactyls (about 10 species) that includes pigs and hippopotamuses (Fig. 206). Their second and fifth digits are relatively well-developed, and their canines are large. Their molars are tuberculate, meaning food is chewed in the Mouth before swallowing. The Stomach is relatively simple, and food is not regurgitated for remastication.

Russia is home to a single species of wild pig—the wild boar (Sus scrofa)—which is widespread across the central, southern, and northwestern Regions of the country and serves as the ancestor of many domestic pig breeds. It inhabits damp forests and reed thickets. It reproduces once a year, producing a litter of 4 to 6 young. In domestic pigs, the number of piglets is significantly higher As a result of selective breeding, which has also led to an increased number of teats. Other species of wild pigs are found in South Asia and Africa, while peccaries, which are closely related to pigs, inhabit South and Central America.

The hippopotamus (Hippopotamus amphibius) is a large (body weight up to 4 t) semi-aquatic mammal with bare Skin that cannot tolerate drying out. It is distributed throughout sub-Saharan Africa, inhabiting rivers and lakes and only rarely coming ashore. It feeds on aquatic vegetation. The pygmy hippopotamus (Choeropsis liberiensis) is noticeably smaller than the common hippo, with a body weight of 250 – 270 kg. Native to Central Africa, it is listed on the IUCN Red List.