THE DEVELOPMENT OF WHALES.

New Zealand Herald, Volume XLIX, Issue 15175, 14 December 1912, Page 5 (Supplement)

THE DEVELOPMENT OF WHALES.

The study of fossils and embryos has succeeded .in proving, says Professor Kukenthal, the foremost authority, on cetaceans, that whales are descended from ancient land beasts of prey— creodonts. In the long process of evolution changes have been wrought which enable these monster mammals to handle themselves in the water with as much ease as if they were veritable fishes.

The embryo in its first development is built after the type of a land mammal; the head is cleanly separated from the body by a neck, the jaws are equipped with a full set of teeth, what • would be the limbs ' are plainly indicated, and there is reason to believe that at one stage the embryo is covered with a coat of fur.

Life in the water first caused a slow decrease of specific weight, giving the whale gradually the ability to float on;the surface. This was brought about principally by the accumulation of a thick layer of fat under the skin, and the growth of airspaces in the enormous skull, which in some whales measures a third of the entire body.

The incredible speed that the development of the powerful tail-fin made possible, caused lli3 elimination of all projecting organs that might increase ■ friction. Thus the spindle-shaped body is perfectly smooth; only on its. back is generally a narrow projection, which acts as a keel.

Diving also has had its influence'on the alteration of the body. Sometimes, as in the case of the largo-toothed whales that feed on cuttlefish, they go to a depth of a thousand yards or more. The openings of the body then close tight,, to , resist;; increasing pressure. Nature has provided the nose with a curious valve arrangement, the - little eye is surrounded by a covering as hard as iron and fortified by powerful muscles, and the 'whole body is protected by a tremendous covering of, fat. \ ; - : I

With these curious changes has come an enormous increase in size, until, the whale, which descended, from a comparatively small animal, is now the largest that lives, for its weight ", riot, uncommonly reaches sixty or seventy tons. ■ ' •

It would seem impossible for the mother to provide the young whale with ,unwatered milk, but evolution has solved the,problem in this wise: the milk is first collected in a . container in . the mother's body, - and then by a specially adapted muscle it "is squirted: directly into the baby's mouth without coming in contact with the -water.