The animal grows to a length of at any rate 14 feet. The limbs and the tail are short. Like other aquatic animals the nostrils are on the surface of the head, and can be closed when the animal is under water. When it reaches the surface of the water after a prolonged immersion, it spouts like a Whale. Sir Samuel Baker says that ten minutes is the longest time that the Hippopotamus can remain below the water. It is frequently a dangerous animal to encounter, as it will capsize boats, and even bite large pieces out of their bottoms; with its huge teeth it {275} can and does attack and destroy human beings. The Hippopotamus not only swims, but can walk along the bottom of a river with great rapidity. It occasionally puts out to sea from the mouths of rivers frequented by it; and it is supposed that in this way Madagascar was populated with Hippopotamuses, whose remains are now found in swamps in that island. [Illustration] FIG. 141.--Wild Boar. _Sus scrofa._ x 1/12. FAM. 2. SUIDAE.--The Pig family, Suidae, differ from the last in their smaller size, in the terminal nostrils and mobile snout, which is not grooved, except faintly as in _Babirusa_. They are generally hairy, but the Babyroussa is an exception, while _Phacochoerus_ is but slightly haired. Though there are four digits, as in the Hippopotamus, only two reach the ground in walking. The stomach, furthermore, is simple, and (except in _Dicotyles_) there is a caecum. The kidneys are smooth, and the liver is more lobate than in _Hippopotamus_. The orbital cavity is confluent with the temporal fossa. The typical genus, _Sus_, is distributed over Europe, Asia, and the islands of the Malay Archipelago, reaching as far as Borneo and Celebes. The dentition[185] is complete. A single species, the so-called _S. sennaariensis_, is from Ethiopian Africa, but it is not certain how far this animal may be an escaped species introduced by man. A very large number of "species" of _Sus_ have been described, but Dr. Forsyth {276} Major is disposed to reduce them to four if not to fewer species. He allows the widely-ranging _S. scrofa_, _S. vittatus_, and the eastern Malayan _S. verrucosus_ and _S. barbatus_. [Illustration] FIG. 142.--Pygmy Hog (from _Nature_). _Sus salvania._ x 1/6.