Family 47.—SUIDÆ. (5 Genera, 22 Species.)
| General Distribution. | |||||
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| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| — 2. 3 — | — 2. 3 — | 1. 2. 3. 4 | 1. 2. 3. 4 | 1. 2. 3. 4 | 1. — — — |
The Swine may be divided into three well-marked groups, from peculiarities in their dentition. 1. The Dicotylinæ, or peccaries (1 genus, Dicotyles). These offer so many structural differences that they are often classed as a separate family. 2. The true swine (3 genera, Sus, Potamochœrus, and Babirusa); and, 3. The Phacochœrinæ, or wart hogs (1 genus, Phacochœrus). These last are also sometimes made into a separate family, but they are hardly so distinct as the Dicotylinæ.
The Peccaries (2 species), are peculiar to the Neotropical region, extending from Mexico to Paraguay. They also spread northwards into Texas, and as far as the Red River of Arkansas, thus just entering the Nearctic region; but with this exception swine are wholly absent from this region, forming an excellent feature by which to differentiate it from the Palæarctic.
Sus (14 species), ranges over the Palæarctic and Oriental regions and into the first Australian sub-region as far as New Guinea; but it is absent from the Ethiopian region, or barely enters it on the north-east. Potamochœrus (3 species?), is wholly Ethiopian (Plate V. vol. i. p. 278). Babirusa (1 species), is confined to two islands, Celebes and Bouru, in the first Australian sub-region.
Phacochœrus (2 species), ranges over tropical Africa from Abyssinia to Caffraria.
Dr. J. E. Gray divides true swine (Sus) into 7 genera, but it seems far better to keep them as one.
Fossil Suidæ.—These are very numerous. Many extinct species of wild hog (Sus), are found in Europe and North India, ranging back from the Post-pliocene to the Upper Miocene formations. In the Miocene of Europe are numerous extinct genera, Bothriodon, Anthracotherium, Palæochœrus, Hyotherium, and some others; while in the Upper Eocene occur Cebochœrus, Chœropotamus, and Acotherium,—these early forms having more resemblance to the peccaries.
None of these genera are found in America, where we have the living genus Dicotyles in the Post-pliocene and Pliocene deposits, both of North and South America; with a number of extinct genera in the Miocene. The chief of these are, Elotherium, Perchœrus, Leptochœrus, and Nanohyus, all from Dakota, and Thinohyus, from Oregon. One extinct genus, Platygonus, closely allied to Dicotyles, is found in the Post-pliocene of Nebraska, Oregon, and Arkansas. Elotherium is said to be allied to the peccary and hippopotamus. Hyopotamus, from the Miocene of Dakota, is allied to Anthracotherium, and forms with it (according to Dr. Leidy) a distinct family of ancestral swine.
It thus appears, that the swine were almost equally well represented in North America and Europe, during Miocene and Pliocene times, but by entirely distinct forms; and it is a remarkable fact that these hardy omnivorous animals, should, like the horses, have entirely died out in North America, except a few peccaries which have preserved themselves in the sub-tropical parts and in the southern continent, to which they are comparatively recent emigrants. We can hardly have a more convincing proof of the vast physical changes that have occurred in the North American continent during the Pliocene and Post-pliocene epochs, than the complete extinction of these, along with so many other remarkable types of Mammalia.