Whale

whale, aquatic mammal of the order Cetacea, found in all oceans of the world. Members of this order vary greatly in size and include the largest animals that have ever lived. Cetaceans never leave the water, even to give birth. Although their ancestry has been much debated, DNA studies and skeletal evidence from extinct early whales indicate that whales evolved from the ancestors of artiodactyls, a group that includes hippopotamuses, cows, pigs, and deer.

Characteristics and Behavior

Like other mammals, whales breathe air, are warm-blooded, and produce milk to feed their young. Their adaptations for aquatic life include a streamlined form, nearly hairless skin, and an insulating layer of blubber, which can be as thick as 28 in. (70 cm) in some Arctic species. The forelimbs of whales are modified into flippers, and the hind legs are reduced to internal vestiges. Many species possess a dorsal fin. The tail is flattened into horizontal flukes and is used for propulsion. The head is very large, with a wide mouth and no external neck.

Whales have one or two nostril openings, called blowholes, located far back on the top of the head; the nostril valves close and the lungs compress when the whale dives. Most whales must surface every 3 to 20 min to breathe, but some, like the sperm whale, can remain submerged for more than an hour. Spouting occurs when the whale surfaces and clears water from its blowhole along with any moisture trapped in its air passages. The shape of the spout is characteristic of each type of large whale. Whales have small eyes, designed to withstand great pressures, and most species have good vision. Their hearing is also excellent. Many cetaceans have highly convoluted brains larger than those of humans, and whales are believed to be extremely intelligent.

Most large whales travel in small schools, or pods, but some, like the fin whale, swim alone or in pairs; small cetaceans form schools of up to several thousand individuals. Most large whales are found in open ocean, where they migrate thousands of miles between feeding and breeding grounds. Dolphins frequently live in coastal waters. A few dolphin species are found in tropical rivers. Females of most species give birth to a single calf every two to three years. Gestation periods range from 9.5 to 17 months. The newborn calf is pushed to the surface by the mother or by another adult; it is able to swim almost immediately and is nursed for 6 to 12 months. Some large whales are believed to have lived 100 years or more in the wild.

Types of Whales

There are two major groups of whales—the toothed whales (suborder Odontoceti) and the toothless baleen whales (suborder Mysticeti).

Toothed Whales

Toothed whales include two families that are widely distributed, the beaked and bottlenose whales (family Ziphiidae) and the sperm whale, or cachalot (family Physeteridae); the beluga, or white whale, and the narwhal (family Monodontidae), small polar whales with no dorsal fin and only a few teeth; the river dolphins (family Platanispidae), which inhabit muddy rivers of India and South America; and several families better known as ocean dolphins and porpoises. The killer whale and pilot whale are types of dolphin. The white whale Moby-Dick, of Herman Melville's novel, was not a beluga but a sperm whale with prominent white features.

Toothed whales range in length from 4 to 60 ft (1.3–18.5 m). They catch fast-moving prey, like fish or squid. Many species use echolocation (sonar) for underwater navigation and hunting. They have a single blowhole and a wide throat to accommodate large prey. Some of the larger ones, like the sperm whale, can dive as deep as 1 mi (1.6 km).

Toothless Whales

There are three families of baleen whales: the right whale family (Balaenidae), including the bowhead, or Greenland whale; the gray whale family (Eschrichtidae), with a single species (Eschrichtius robustus) found in the N Pacific Ocean; and the rorqual family (Balaenopteridae). Rorquals, the most familiar of the large whales, have large, pouchlike throats with furrows running from mouth to belly. The family includes the humpback whale, the sei whale, the minke whale, the Bryde's whale, the fin whale (or common rorqual), and the blue whale, which can grow to a length of 100 ft (30 m) and a weight of 150 tons.

Baleen whales are large species, usually over 33 ft (10 m) long. They are filter feeders, living on shrimplike krill, plankton, and small fish. They lack teeth but have brushlike sheets of a horny material called baleen, or whalebone, edging the roof of the mouth. With these strainers and their enormous tongues, tons of food can be separated from seawater. Baleen whales have narrow throats and paired blowholes. Male humpbacks produce a repeated pattern of sounds called a song during the mating season; the purpose is not clear, as all males in a group sing basically the same song.

Whaling

All species of large whales have been drastically reduced in numbers by centuries of intensive whaling. An indefinite ban by the International Whaling Commission on commercial whaling of all large whales gradually went into effect following the 1984–85 season, and large portions of ocean have been designated whale sanctuaries. With these and various other protective efforts, some species have begun to return to acceptable numbers, but others, especially the right and blue whales, are still rare and endangered. After decades of protection the number of E Pacific gray whales seems to have returned to its estimated prewhaling level. Only the small minke whale exists in populations great enough for sustainable whaling to be considered. Whale products include whale oil, sperm oil, spermaceti, ambergris, and whalebone, as well as meat, bone meal, and liver oil. Natural and synthetic materials have replaced all whale products in the United States. See separate entry on whaling for more information.

Classification

Whales are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Cetacea.

Bibliography

See R. Ellis, The Book of Whales (1980) and Dolphins and Porpoises (1989); L. Watson, Sea Guide to Whales of the World (1981).

---

whale

Any of dozens of species of exclusively aquatic mammals found in oceans, seas, rivers, and estuaries worldwide but especially numerous in the Antarctic Ocean. Whales are commonly distinguished from the smaller porpoises and dolphins and sometimes from narwhals, but they are all cetaceans. See also baleen whale; toothed whale.

---

whale

1. any of the larger cetacean mammals, excluding dolphins, porpoises, and narwhals. They have flippers, a streamlined body, and a horizontally flattened tail and breathe through a blowhole on the top of the head

2. any cetacean mammal

3. Slang a gambler who has the capacity to win and lose large sums of money in a casino

---

whale [wāl]

(vertebrate zoology)

A large marine mammal of the order Cetacea; the body is streamlined, the broad flat tail is used for propulsion, and the limbs are balancing structures.

---

Whale [wāl]

(astronomy)

Cetus

---

whale

former symbol of demonic evil. [Animal Symbolism: Mercatante, 26]

See : Demon

---

whale

many species in danger of extinction, owing to massive hunting. [Ecology: Hammond, 290]

See : Extinction

---

whale

lures fish to mouth with sweet breath. [Animal Symbolism: Mercatante, 27]

See : Treachery

---

Whale

any one aquatic mammal of the order Cetácea. Length, 1.2–33 m. The fusiform, gently streamlined bare body merges imperceptibly with the laterally compressed tail, which ends in a horizontal, bilobed fin. The anterior extremities evolved into fins and the posterior ones disappeared, although the remnants of the pelvic bone are still found deep in the posterior muscles. The hair, the sebaceous and sweat glands, and external ear are reduced. Under the skin there is a thick layer of fat. Whales do not have mobile lips. From the outside, the neck is insignificant. The valved nostrils, of which there are one or two, open on the sinciput. The lungs are very elastic. The testes are concealed in the abdominal cavity. In the female, the teats are embedded in pouches of skin located in the posterior half of the body on either side of the urogenital groove. Whales have spongy skeletons. The facial bones are drawn out into a pointed rostrum. The vertebral column lacks a sacral segment. There are about 17 pairs of ribs, one to 11 pairs of which are connected to the sternum.

Because of the low sensitivity of the cetacean respiratory center of the medulla to the accumulation of CO 2 in the blood, whales can remain under water for a long time without coming up for air. (Sperm whales can stay submerged for about 1½ hours.) The whale’s low sensitivity to CO₂ is due to an abundance of myoglobin—a substance that gives the muscles a dark color and makes possible the transfer of a large quantity of oxygen from the surface of the water to the oxygen reserves in the capillary network (the “miraculous network”). When the animal submerges, the heartbeat slows sharply, and the blood flow is redistributed in such a way that the brain and heart muscle are the first to receive oxygen. The muscles obtain oxygen from the myoglobin.

Of the whale’s sense organs, the auditory ones are the best developed. Because the right and left ears are separated from the skull bones by air chambers filled with foam, whales can determine accurately the direction from which a sound is coming. Sound is transmitted to the inner ear through a narrow auditory canal and middle ear ossicles as well as through the lower jaw, which is innervated by a branch of the trigeminal nerve. The tympanic membrane resembles a folded umbrella. Taste, touch, and skin sensitivity are well developed. Vibrissae located in the head are the whale’s tactile organs. Vision plays a subordinate role. The eyes are small, with a spherical crystalline lens and thick, flattened cornea. The tear glands have virtually disappeared. In the course of evolution, whales have lost their sense of smell.

The order of whales is divided into two suborders: the toothless, baleen, or whalebone (Mysticeti) and toothed (Odontoceti) whales. The toothless whales include three families: right whales (Balaenidae), rorquals or finback whales (Balaenopteridae), and gray whales (Eschrichtiidae). The toothed whales are subdivided into four families: sperm whales (Physeteridae), beaked whales (Ziphiidae), dolphins and porpoises (Delphinidae), and river dolphins (Platanistidae).

In the oceans of the world from the arctic to the antarctic there are 38 genera of whales, including 83 species. There are 25 genera in Soviet waters, including 32 species (mostly dolphins). Many whales migrate regularly within the northern and southern hemispheres, going to warm waters in winter to reproduce and to cold waters in summer to fatten. Between 1924 and 1969 about 11,000 whales were tagged by scientists. The experiment revealed that toothless whales travel about 5,000–10,000 km. Normally, however, they do not cross the equator, and they return to the same localities.

Toothed whales feed primarily on fish and cephalopod mollusks, whereas the main food of toothless whales is planktonic crustaceans, which are filtered through the whalebone. Toothed whales have from two to 240 teeth.

Whales usually give birth to one large calf once every two years. (The calf may be one-third to one-half the length of the mother’s body. Some whales give birth more often because they are able to mate even before the period of lactation is over.) The lactation period ranges from four months in small dolphins to one year in sperm whales. Almost three times richer in protein and ten times richer in fat than cow’s milk, whale milk helps the young whales to develop quickly. Sexual maturity is reached in two to six years. The life span ranges from 30 to 50 years. Whales travel in families or schools.

The ancestors of the whales (probably predatory Creodonta) evolved into aquatic animals almost 60 million years ago. A total of 127 genera of extinct whales are known. Fossil remains of the most ancient whales (archaeocetes) are known from the Lower Eocene epoch. Dating from the Upper Eocene are fossils of primitive toothed whales (Squalodontidae), and from the Middle Oligocene, fossils of the most ancient toothless whales (Cetotheriidae). The right and rorqual whale families appeared in the Miocene epoch. In the USSR fossil whales have been found in Lower Oligocene strata in the Caucasus and in Upper Miocene strata in Moldavia, the Crimea, and the Caucasus.

Whaling is regulated by the International Whaling Commission. Because of the complete ban on hunting certain toothless whales, the number of them has tended to increase.

REFERENCES

Sleptsov, M. M. Kitoobraznye dal’nevostochnykh morei, 2nd ed. Vladivostok, 1955.
Tomilin, A. G. Kitoobraznye. Moscow, 1957. (Zveri SSSR i prilezhashchikh stran, vol. 9.)
Tomilin, A. Kitoobraznye fauny morey SSSR. Moscow, 1962.
Zemskii, V. A. Kity Antarktiki. Kaliningrad, 1962.
Zhizn’ zhivotnykh, vol. 6. Moscow, 1971.
Iablokov, A. V., V. M. Bel’kovich, and V. I. Borisov. Kity i del’finy. Moscow, 1972.
Slijper, E. J. Whales. London, 1962.
Whales, Dolphins, and Porpoises. Edited by K. S. Norris. Berkeley-Los Angeles [Calif.] 1966.

A. G. TOMILIN