Hippopotami's , (Gr. horse, and river), a pachydermatous animal, inhabiting Africa. It is generally called sea cow by the Cape colonists, a term which is usually applied in America to the manatee. The dental formula is: four incisors in each jaw, long, cylindrical, pointed, and inclined forward below, short, conical, and curved above; canines four, resembling the incisors of rodents, the upper ones straight, the lower thick and bent, overlapping the upper; the molars six on each side in each jaw, the anterior three more pointed, and the posterior with the points in the adult worn in a trefoil shape. Its powerful jaws, sub-cylindrical lower incisors, and chisel-edged canines are formed for tearing and crushing rather than grinding the coarse tough plants and aquatic roots and grasses upon which it principally feeds; the canines seem excessively developed. In its skull the hippopotamus resembles the hog in the connection of the bones and their su-tures, in other respects being more like the ox; the skeleton is very massive, indicating the great size and strength and rather slow locomotive powers of the animal.
The skull is remarkable for the horizontal plane of its upper portion, the eyes, nostrils, and ears of the animal when in the water being nearly upon the same level, and the upper part of the head, when this alone is visible, looking not unlike that of a horse; the bony orbits are very prominent, projecting above the top of the skull. The stomach is multiple, something as in ruminants, though it is not known to chew the cud; it can contain five or six bushels of vegetable matter, and the large intestine is about 8 in. in diameter; the intestinal canal, without caecum, is nearly 12 times as long as the body, considerably more than 120 ft. The average length of the male from the end of the nose to the tip of the tail (the latter being about a foot) is 14 ft., but they have been known to measure 17ft.; the females are much smaller; the girth is nearly equal to the length, and the height at the shoulders between 5 and 6 ft.; the aperture of the mouth is about 2 ft. wide, and the tusks are more than a foot long.
This huge uncouth body, of a form between that of an over-fed pig and a fattened ox, is supported on short stout limbs, with four toes on each small foot, nearly equal and with short hoofs; the massive head is broad, and the expression of the face singular from the high position of the eyes; the lips are wide and tumid, especially the upper, concealing the teeth when the mouth is shut, and furnished with a few tufts of hair; the nose is broad and truncated, and the nos-trils, on the end and capable of protrusion so that the animal may breathe when all the body is under water, may be closed during submer-sion; the prominent eyes enjoy great freedom of motion, and may be protruded or retracted to adapt its vision to an air or water medium; the last two contrivances are admirably adapted for the protection of an aquatic animal so wary and sluggish as the hippopotamus. The head is contracted behind the angles of the mouth, and the forehead is broad and flat; the ears are only 3 or 4 in. long, fringed and lined internally with a fine hair, just behind and but little above the eyes; the eyebrows are tumid, which makes the eyes appear deeply seated; the neck is short, thick, and hog-like, the back slightly arched, the body cylindrical, the nates full, the pendent abdomen almost touching the ground, the tail short, robust, and edged with wiry hairs, the mammae two in number and ventral, and the skin nearly naked.
The color, when the skin is dry, is reddish gray, brownish on the back, lighter beneath; under water the colors are various shades of blue. Prof. Owen, in the " Annals and Magazine of Natural History," vol. v., 1850, gives some interesting particulars from a young living specimen received at the zoological gardens of London in 1850, the first seen alive in Europe since the time of the emperor Gordian III. in Rome in the 3d century. This animal was captured on the banks of the Nile in August, 1849, and was supposed to have been recently brought forth, as it was not much larger than a new-born calf, though stouter and shorter legged; it arrived in London in May, 1850, and was accordingly then about ten months old, yet it was 7 ft. long and of 6 1/2 ft. girth in the middle of the body. The hind limb was buried in the skin of the flank nearly to the prominence of the heel; there was no trace of a glandular orifice, as in the rhinoceros, behind each foot; the naked skin, of a dark India-rubber color, and with fine transverse wrinkles, glistened with a sebaceous secretion as the animal emerged from the water; the eyes had a thick nicti-gating membrane, and the mouth a peculiar upward curve of its angles toward the eyes, which gave a comical expression to the massive countenance.
Apparently in perfect health, it breathed three or four times in a minute, slowly and regularly; its food consisted of a kind of porridge of milk and maize meal, though it was more than half weaned from its baby diet. Other specimens have since been received at the zoological gardens, and also at the Paris jardin des plant es, and one has been exhibited in the United States. Several species are described, but the best known and most extensively distributed is the H. amphi-bius (Linn.), which was formerly found from Egypt to the Cape of Good Hope in all the large rivers, though now it is rare except in the lonely regions explored by Livingstone and dimming. Of whatever species, they spend most of their time in the water, lolling about in a dreamy manner, frolicking like a porpoise, or wallowing in the mud like a hog; they leave the rivers chiefly at night to crop the succulent grasses on their banks, especially in localities where brushwood abounds; they are also fond of passing the day in the ocean, near the mouths of rivers.
Though clumsy upon the land, their movements in the water are graceful and rapid; they are gregarious, and both sexes delight to congregate at all seasons of the year in Small herds; they can remain under water for about 15 minutes, walking upon the bottom, and probably longer if necessary; but it is not known whether this ability to sustain prolonged immersion is owing to an apparatus like the venous reservoirs of the seals, the arterial plexi-form receptacles of the whales, or some other equivalent structure. They are playful, peaceable, and inoffensive when undisturbed; but if wounded, and especially if in company with their young, they are savage and eager to assail any enemy; the males in the love season are quarrelsome, and both sexes are often seen covered with scars; it is said that the young males are often killed by the older ones. The males are darker colored than the females. The period of gestation is about nine months, and a single young one is brought forth on land, taking to the water instantly when alarmed; the very young ones are carried in the water on the neck of the mother, and when they grow older on the withers.
When they blow, they puff up the water about 3 ft. high, according to Livingstone. The sagacity of the hippopotamus, though inferior to that of the elephant, is considerable, as evinced by its adroitness in avoiding its enemies on land or in the water, its escaping from pitfalls and other stratagems of the natives, its going with its young to distant localities when annoyed by man, and its caution in exposing itself even in its watery abode when it has been once assailed. They are hunted for their flesh, which resembles pork; for the speck or layer of fat just under the skin, a bonne bouehe for the Cape Town epicure; for their teeth, which are valuable articles of trade, and were formerly much employed for their hardness in the manufacture of artificial teeth, and for various ornamental purposes; and for their tough skin, which is made into shields and helmets, and cut into cylindrical strips, which form the whips of the Cape colonists. The voice of the animal is between a grunt and a neigh, and has been compared by travellers to a variety of discordant sounds. Its voracity is very great, and its destruction of the native crops, both by devouring and treading them down, has been known and deplored from the earliest antiquity.
Besides man, the principal enemy of the hippopotamus, and in its own element, is the crocodile; the ancients believed that an inextinguishable enmity existed between these animals, but both are so well armed and defended that they probably do not very often attack each other. This animal was well known to the ancients, and it figures under many shapes in their writings; accurate representations are given on Roman coins and Egyptian sculptures; it was occasionally seen in their triumphal pomps and gladiatorial shows. Since the time of Bochart the behemoth of the Hebrews has been supposed by many to be the hippopotamus, and some of the verses in the 40th chapter of Job well apply to this animal; some authors, however, Milton among the rest, deny that these animals are the same, without throwing any light upon what the behemoth really is. - For interesting details on the method of hunting these unwieldy creatures, see Gordon Cumming"s "Hunter's Life in Africa," and An-dersson's "Lake Ngami, or Explorations and Discoveries during Four Years' Wanderings in the Wilds of S. W. Africa;" and for notices of their character and habits, Livingstone's "Travels and Researches in South Africa." - The hippopotamus is found fossil in the tertiary and diluvial formations of Europe and Asia.