HIPPOPOTAMUS ("river-horse," Gr. linros, horse and Trora^tos, river), the name of the largest representative of the non-ruminating artiodactyle ungulate mammals, and its living and extinct relatives. The common hippopotamus ( Hippopotamus amphibius), which formerly inhabited all the great rivers of Africa but whose range has now been much restricted, is most likely the behemoth of Scripture, and may very probably in Biblical times have been found in the Jordan valley, since at a still earlier (Pleistocene) epoch it ranged over a large part of Europe. It typifies not only a genus, but likewise a family, Hippopotamidae, distinguished from its relatives the pigs and The Hippopotamus (Hippopotamus amphibius).
peccaries, or Suidae, by the following assemblage of characters: Muzzle very broad and rounded. Feet short and broad, with four subequal toes, bearing short rounded hoofs, and all reaching the ground in walking. Incisors not rooted but continuously growing; those of the upper jaw curved and directed downwards; those of the lower straight and procumbent. Canines very large, curved, continuously growing; upper ones directed downwards. Premolars ^; molars f. Stomach complex. No caecum.
In form the hippopotamus is a huge, unwieldy creature, measuring in the largest specimens fully 14 ft. from the extremity of the upper lip to the tip of the tail, while it ordinarily attains a length of 12 ft., with a height of 5 ft. at the shoulders, and a girth round the thickest part of the body almost equal to its length. The small ears are exceedingly flexible, and kept in constant motion when the animal is seeking to catch a distant sound; the eyes are placed high up on the head, but little below the level of the ears; while the gape is wide, and the upper lip thick and bulging so as to cover over even its large tusks when the mouth is closed. The molars, which show trefoil-shaped grindingsurfaces are well adapted for masticating vegetable substances, while the formidable array of long spear-like incisors and curved chisel-edged canines or tusks root up rank grass like an agricultural implement. The legs are short, so that the body is but little elevated above the ground; and the feet, which are small in proportion to the size of the animal, terminate in four short toes each bearing a small hoof. With the exception of a few tufts of hair on the lips, on the sides of the head and neck, and at the extremity of the short robust tail, the skin of the hippopotamus, some portions of which are 2 in. in thickness, is destitute of covering. Hippopotamuses are gregarious animals, living in herds of from 20 to 40 individuals on the banks and in the beds of rivers, in the neighbourhood of which they most readily find appropriate food. This consists chiefly of grass and of aquatic plants, of which these animals consume enormous quantities, the stomach being capable of containing from 5 to 6 bushels. They feed principally by night, remaining in the water during the day, although in districts where they are little disturbed they are less exclusively aquatic. In such remote quarters they put their heads boldly out of the water to blow, but when rendered suspicious they become exceedingly cautious in this respect, only exposing their nostrils above the water, and even this they prefer doing amid the shelter of water plants. In spite of their enormous size and uncouth form, they are expert swimmers and divers, and can remain easily under the water from five to eight minutes. They walk on the bottoms of rivers, beneath at least i ft. of water. At nightfall they come on land to feed; and when, as often happens on the banks of the Nile, they reach cultivated ground, they do immense damage to growing crops, destroying by their ponderous tread even more than they devour. To scare away these unwelcome visitors the natives in such districts are in the habit of kindling fires at night. Although hippopotamuses do not willingly go far from the water on which their existence depends, they occasionally travel long distances by night in search of food, and in spite of their clumsy appearance are able to climb steep banks and precipitous ravines with ease. Of a wounded hippopotamus which Sir S. Baker saw leaving the water and galloping inland, he writes: " I never could have imagined that so unwieldy an animal could have exhibited such speed. No man could have had a chance of escape." The hippopotamus does not confine itself to rivers and lakes, but has been known to prefer the waters of the ocean as its home during the day. Of a mild and inoffensive disposition, it seeks to avoid collision with man; when wounded, however, or in defence of its young, it exhibits great ferocity, and native canoes are capsized and occasionally demolished by its infuriated attacks; the bellowing grunt then becoming loud enough to be heard a mile away. As among elephants, so also among hippopotamuses there are " rogues " old bulls which have become soured in solitude, and are at all times dangerous. Assuming the offensive on every occasion, they attack all and sundry without shadow of provocation; and the natives avoid their haunts, which are usually well known.
The only other living species is the pygmy hippopotamus, H. (Choeropsis) liberiensis, of West Africa, an animal not larger than a clumsily made pig of full dimensions, and characterized by having generally one (in place of two) pair of incisors. It is much less aquatic than its giant relative, having, in fact, the habits of a pig.
A small extinct species (H. lemerlei) inhabited Madagascar at a comparatively recent date; while other dwarf kinds were natives of Crete (H. minutus) and Malta and Sicily (H . penllandi) during the Pleistocene. A large form of the ordinary species (H. amphibius major) was distributed over Europe as far north as Yorkshire at the same epoch; while an allied species (H. palaeindicus) inhabited Pleistocene India. Contemporary with the latter was, however, a species (H. namadicus) with three pairs of incisors; and " hexaprotodont " hippopotamuses are also characteristic of the Pliocene of India and Burma (H. sivdensis and H. iravadicus), and of Algeria, Egypt and southern Europe (H. hipponensis). For the ancestral genera of the hippopotamus line, see ARTIODACTYLA. (R. L.*)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)