The Living World of Nature [antikvár]

The great whales, now the largest animals in existence, are placid, fish-litce mammals inhabiting the great oceans. In modern times, the end for most of them comes about in a wetterMammals are defined as that" ----dass of animals with warm blood and a covering of hair, which breathe atmospheric air and suckle their young. In the whales the hair has practically disappeared, and the form has become fish-like, due to their highly specialised aquatic existence. But the whale still has to surface to breathe, has warm blood, and supplies its young with milk from typical mammary glands. The whale is, therefore, a mammal just as much as the horse or the dog.Just how and when the whale became transformed and so highly specialised in its marine existence, is not precisely known. As a result of its entirely aquatic existence, however, its large size is no handicap in modem times, and it has survived the gigantic reptiles which roamed the earth in remote times. Despite its fish-like appearance, the whale is still a quadruped under its skin. The lateral fins are still arms of articulate bone, while in its hind body, deep in the layer of blubber, can still be seen the vestigial hind legs.The biggest of the whales of the present day reach a length of more than ninety feet and weigh something over a tonA fine example of the common whale. The stein of the bactc is btuish and the iridescent plume which rises from the air-twles may reach a height of 15-16 feet.and caudal fin.of blood and foam caused by a harpoon wedged inexorably in their enormous flanks. Modern whalers are the great predators on whales generally.for every foot. The body is thick-set and massive, and the - _whale is the only mammalwhich cannot move its head on----------its neck. In adult whales theskin is smooth, oily and almost completely bare (in young whales, at least a few bristles appear on the snout and chin). Under the skin there is a thick layer of fat surrounding the whole body. This repels cold, maintains the body at uniform temperature in the cold seas, and provides a reserve of nourishment during periods when the whale has to go short of his normal food supply.The adult whale's l)ody colour is usually blue. Young are much lighter in colour and are white about the throat, eyes Surfacing only to take in air, the whale is provided with great lungs which enable him to stay submerged for long periods and often at great depths. Each time he surfaces to take in new supplies of air, he blows the used air through his nostrils. These are placed close together on top of his head and are usually referred to as blow-holes. This jet of air, coming into contact with water and the cold atmosphere, forms the beautiful white plume that appearsThe whale, like most mammals, is strongly; attached to her young.^ She protects it, guides it, and is ready to face death in its defence. The young whale is known as a calf; it suckles its mother like any other young mammal.The characteristic teeth of the baleen whale constitute a kind of fringe which filters out the smallfish and crustaceans on which this giant mammal lives. This is a case where the largest of the mammals feeds on the smallest of prey.