Natural History of the Mammalia of India and Ceylon

Order Cetacea — The Whales

These curious creatures have nothing of the fish about them, save the form, and frequently the name. In other respects they are warm-blooded, viviparous mammals, destitute of hinder limbs, and with very short fore-limbs completely enclosed in skin, but having the usual number of bones, though very much shortened, forming a kind of fin. The fin on the back is horizontal, and not rayed and upright like that of a fish; the tail resembles that of a fish in form, the caudal vertebræ running through the middle of it. The immense muscular power of this tail, with its broad flanges, arises from the flesh of the body, terminating in long cords of tendon, running to the tip. The vertebral column is often ankylosed in the fore-part, but is extremely elastic, owing to the cartilaginous cushion between each bone in the latter half. Thus, whilst the fore-part is rigid, the hinder is flexible in the extreme. The brain is large and much convoluted; the heart is very large, and the blood-vessels extremely full and numerous, with extensive ramifications, which, being filled with oxygenated blood, assist in supporting life whilst submerged. The lungs are also very large. The laryngeal and nasal passages are peculiar. The following description is by Dr. Murie: “In front of the larynx of man we all know that there is an elastic lid, the epiglottis, which folds over and protects the air passage as food is swallowed. The side cartilages constitute the walls of the organ of voice and protect the vocal chords. Now, in the comparatively voiceless whale, the cartilages, including the epiglottis, form a long rigid cylindrical tube, which is thrust up the passage at the back of the palate in continuity with the blow-hole. It is there held in place by a muscular ring. With the larynx thus retained bolt upright, and the blow-hole being meanwhile compressed or closed, the cetacean is enabled to swallow food under water without the latter entering the lungs.” The stomach is peculiar, being composed of several sacs or chambers with narrow passages between; the intestines are long, glandular and, according to Dr. Murie, full of little pouches. There is no gall bladder; the gullet is very narrow in some and wider in others. Some have teeth, others are without. The eyes are small; the ears deficient externally, though the interior small ear-bones of ordinary mammals are in these massive and exceedingly dense, so much so, as Murie observes, as to be frequently preserved fossil when other osseous structures are destroyed.

The cetacea have been divided into the Denticete, or Toothed Whales, and the Mysticete, or Whalebone Whales. The former contains the river dolphins, the ziphoid whales, the gigantic sperm whale, the sea dolphins, and the narwhal or sea unicorn. The latter contains the baleen whales.