UNDER the heading of cetaceans are grouped the whales, dolphins and porpoises. They are all carnivorous creatures living in the sea and are very widely distributed. All the whalebone whales, which are toothless, are placed in one family, and all other groups consist of toothed whales.
In the toothless whales there is a total absence of teeth in the adult, their place being taken by a number of plates of ‘baleen ‘or whalebone. The Greenland or ‘Right ‘Whale is typical of this family. It is from forty to sixty feet in length, nearly one-third of the length being made up by the head. On account of the absence of teeth and the extremely small size of the gullet, a whale is compelled to live on very small creatures. He swims with his mouth open, and encloses an enormous amount of water containing myriads of diminutive marine animals. He then shuts his mouth and allows the water to strain through the whalebone plates, retaining the food, which he is then able to swallow.
Owing to the fact that many whales are protected against the cold of the water in which they live by a thick coating of fat, known as ‘blubber,’ they have long been pursued by man, and in some species the numbers have decreased almost to the point of extinction. Members of this family are the rorquals, the largest of all living creatures, some being known to reach a hundred feet in length.
The sperm whales, or cachalots, are very remarkable. The males are very long, from fifty to seventy feet, but the females are much smaller. The head takes up more than a third of the entire length of the body. The snout forms a broad, truncated mass, with the nostrils placed in the front. These whales live together in numbers, known as ‘schools,’ and are found usually in tropical waters. The spermaceti, for which they are specially pursued, is in life a clear, white, oily liquid, contained in certain cavities of the head. On exposure to the air it solidifies. One whale sometimes yields as much as five hundred gallons. From these whales is also obtained the peculiar substance known as ambergris, which is really a secretion of the intestines caused by disease. It is a waxy-looking substance, used as a basis for perfumes, and is very valuable.
A striking member of the dolphin family is the grampus, a large mammal nearly thirty feet long, often spoken of as the ‘Killer Whale ‘and noted for its extreme ferocity and the
power of its attacks on other cetaceans much larger than itself. Lastly, the curious narwhal must be mentioned. It is an inhabitant of Arctic Seas, and the body alone measures fifteen feet in length. The dentition of this animal is very remarkable. The lower jaw is devoid of teeth, and in the females no external teeth are present in the upper jaw. In the males, the left canine tooth in the upper jaw grows to an enormous tusk of from eight to ten feet, spirally twisted, and continues to grow throughout life. Cases have been known where two such tusks have been developed. Their use seems undoubtedly to be as weapons, and the traces of their effects on the bodies of other narwhals have been observed.