After the humpback’s flipper has been stripped of blubber. The forearm, wrist and fingers are shown. In this species the digits have been reduced to four and are greatly elongated.
The folds are not composed of flesh but entirely of blubber, the layer of fibrous fat which covers the bodies of all whales, porpoises, and dolphins and lies between the skin and the flesh. Since cetaceans are warm-blooded animals (fish and reptiles are cold-blooded) it is necessary for them to have some protection from the cold. Hair is not sufficient for this purpose as in land mammals; consequently the layer of blubber, which acts as a non-conductor and prevents the heat of the animal’s body from being absorbed by the water, has been developed. It is from this that the whale oil of commerce is boiled or tried out. The blubber may be easily peeled off the body in strips called “blanket pieces,” which are cut into blocks and after being sliced are put into the trying out kettles.
The folds on the throat of a finback whale. Probably the folds are an adaptation to increase the mouth capacity and to give greater power of expansion to the lungs.
When one of these great pieces of blubber is being torn off a whale’s body it sometimes gives way and springs back with tremendous force. At the Oshima station in Japan, my cook who had one day been pressed into service when several whales were waiting to be cut in was struck fairly upon the head by a blanket piece and instantly killed; his skull was crushed as though it had been paper and his neck, shoulder, and arm broken. At Aikawa a blubber strip gave way when half the carcass of a humpback was suspended in the air, letting the weight of some fifteen or twenty tons fall upon a cutter standing below; when taken from beneath the whale the poor fellow could hardly be recognized as a human being.
Kyuquot had trouble, also, when a blanket piece struck a flenser’s knife, driving it into his side and injuring him badly. And yet it is surprising what tremendous strength and tenacity the fibrous blubber has. A few inches of it will resist the strain of several thousand pounds, and I have seen a whale drag a ship through the water for half an hour with only two harpoon prongs caught under the blubber of the back.
When a female whale is pregnant the blubber is much thicker and softer than at other times and yields a greater supply of oil; from other causes it may also be very thin, and become hard and dry. The blubber varies in color and may be light yellow, deep pink, or almost white. It is thinnest upon the sides, throat, and breast, and thickest on the “neck” just behind the blowholes, at the dorsal fin, and from that point along the ridge of the back, or “caudal peduncle,” almost to the flukes. On the sides an average thickness in the fin whales is six inches, but just behind the dorsal fin it may reach twelve or fourteen inches.
Since cetaceans live in the water where they do not touch rough surfaces their skins are very soft and smooth; the skin is about half an inch thick and may be separated from the blubber only with difficulty. It is composed of one or more thin outer sheets (epidermis) which may be easily stripped off, leaving exposed the tender under layer (dermis). The skin is perfectly dry and does not possess either the oil (sebaceous) or sweat (sudoriferous) glands usually present in the skins of land mammals. Because of the development of blubber, and the absence of functional hair, such glands are no longer necessary. The skins of some cetaceans, notably the white whale, or beluga, and the bottlenose porpoise are made into leather and furnish the “porpoise hide” of commerce, but that of other porpoises or whales has not been put to extensive commercial use.
A cross section of the folds on the breast of a humpback whale. The upper thin black margin is the skin, then comes the thick white blubber below which is the red flesh.