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Whale is the common name for marine mammals of the order Cetacea. The term whale is sometimes used to refer to all cetaceans in current taxonomy, but in more common English usage it generally excludes the members of the Delphinoidea superfamily, such as dolphins and porpoises. These smaller species belong to the suborder Odontoceti (toothed whales), which also includes the sperm whale, killer whale, pilot whale, and beluga whale. The other suborder of cetaceans, Mysticeti (baleen whales), includes the blue whale, which is the largest animal known to have ever existed, the humpback whale, and many other animals that feed by straining seawater through long strips of baleen that they have in the place of teeth, and from which they get their name.

For centuries, whales have been hunted for meat and as a source of raw materials. By the middle of the 20th century, however, industrial whaling had left many species seriously endangered, and whaling was ended in all but a few countries. Whales are among the most popular animals, with millions of fans and supporters worldwide.

Origins and taxonomy

All cetaceans, including whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulate animals). Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippopotamuses. In fact, whales are the closest living relatives of hippos; they evolved from a common ancestor around 54 million years ago. Whales entered the water roughly 50 million years ago. Cetaceans are divided into two suborders:

• The baleen whales are characterized by baleen, a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. They are the largest whale suborder.
• The toothed whales use sharp teeth and prey on fish, squid, or both. An outstanding ability of this group is to sense their surrounding environment through echolocation.

A complete up-to-date taxonomical listing of all cetacean species, including all whales, is maintained at the Cetacea article.

Anatomy

Like all mammals, whales breathe air into lungs, are warm-blooded, feed their young milk from mammary glands, and have hair, although very little.

The whale body is fusiform. The forelimbs, also called flippers, are paddle-shaped. The end of the tail holds the fluke, or tail fins, which provide propulsion by vertical movement, unlike the horizontal movement of the tails of fish. Although whales generally do not possess hind limbs, some whales (such as sperm whales and baleen whales) have rudimentary hind limbs; even with feet and digits, hidden deep within their bodies. Most species of whale bear a fin on their backs known as a dorsal fin.

Beneath the skin lies a layer of fat called blubber. It serves as an energy reservoir and also as insulation. Whales have a four-chambered heart. Whales have spines, although the neck vertebrae are typically fused, which provides stability during swimming at the expense of flexibility. They have a vestigial pelvis bone.

Whales breathe through their blowholes, located on the top of the head so the animal can remain submerged while breathing. Baleen whales have two; toothed whales have one. Breathing involves expelling excess water from the blowhole, forming a vertical spout. Spout shapes differ between species and learning to recognize these shapes help people identify them.

The Blue Whale is the largest known mammal that has ever lived, and the largest living animal, at up to 35 m (105ft) long and 150 tons.

Whales generally live for 40–90 years, depending on their species, and on rare occasions live over a century. Recently a fragment of a lance which had been used by commercial whalers in the 19th century was found in a bowhead whale off Alaska, showing the whale to be between 115 and 130 years old. Furthermore, a technique for dating age from aspartic acid racemization in the whale eye, combined with a harpoon fragment, indicated an age of 211 years for one male, making bowhead whales the longest lived extant mammal species. Whale flukes often can be used as identifying markings, as is the case for humpback whales. This is the method by which the famous Humphrey the whale was identified in three separate sightings.

Toothed whales such as the sperm whale, possess teeth with cementum cells overlying dentine cells. Unlike human teeth which are comprised mostly of enamel on the tooth portion outside of the gum, whale teeth have cementum outside the gum. Only in larger whales does enamel show where the cementum has been worn away on the tip of the tooth.

Anatomy of the ear

Whales' ears have specific adaptations to their underwater environment. In humans, the middle ear works as an impedance matcher between the outside air’s low impedance and the cochlear fluid’s high impedance. In aquatic mammals such as whales, however, there is no great difference between the outer and inner environments. Instead of sound passing through outer ear to middle ear, whales receive sound through their lower jaw, where it passes through a low-impedance, fat-filled cavity.

Behavior

Whales are widely classed as predators, but their food ranges from microscopic plankton to very large fish and, in the case of orcas, sometimes other sea mammals, even other whales.

Males are called bulls; females, cows. The young are called calves.

Many whales also exhibit other surfacing behaviours such as breaching and tail slapping.

Because of their environment (and unlike many animals), whales are conscious breathers: they decide when to breathe. All mammals sleep, but whales cannot afford to become unconscious for too long because they might drown. It is thought that only one hemisphere of whale brains sleeps at a time, so that whales are never completely asleep, but still get necessary rest. Whales often sleep with only one eye closed.

Some whales communicate with each other using lyrical sounds, called whale songs. These sounds can be extremely loud (depending on the species); sperm whales have only been heard making clicks, because toothed whales (Odontoceti) use echolocation and can be heard for many miles. They can generate about 20,000 acoustic watts of sound at 163 decibels.

Females give birth to a single calf. Nursing time is more than one year in many species, which is associated with a strong bond between mother and young. Reproductive maturity occurs typically at seven to ten years. This mode of reproduction spawns few offspring, but provides each with high survival probability.

The male genitals retract into body cavities during swimming, reducing drag and preventing injury. Most whales do not maintain fixed partnerships during mating; in many species the females have several mates each season. Newborns are delivered tail-first, minimizing the risk of drowning. Whale cows nurse by actively squirting milk so fatty that it has the consistency of toothpaste into the mouths of their young.

Whales are known to teach and learn, as well as cooperate, scheme, and even seem to grieve.

Human effects

Whaling

Some species of large whales are listed by various watchdog groups and governments as endangered due to reduced population resulting from commercial whaling. Large whales have been hunted commercially for whale oil, meat, baleen and ambergris (a perfume ingredient from the intestine of sperm whales) since the 1600s. More than 2 million whales were killed by the modern whaling industry in the early 20th century. By the middle of the 20th century, whaling left many populations severely depleted.

The International Whaling Commission introduced a six year moratorium on all commercial whaling in 1986, which extends to the present day. The moratorium is not absolute, however, and some whaling continues under the auspices of research or aboriginal rights; current whaling nations are Norway, Iceland and Japan and the aboriginal communities of Siberia, Alaska and northern Canada.

Several species of small whales are caught as bycatch in fisheries for other species. In the Eastern Tropical Pacific tuna fishery, thousands of dolphins drowned in purse-seine nets, until preventive measures were introduced. Gear and deployment modifications, and eco-labelling (dolphin-safe or dolphin-friendly brands of tuna), have contributed to a reduction in dolphin mortality by tuna vessels. In many countries, small whales are still hunted for food, oil, meat or bait.

Sonar interference

Environmentalists speculate that sonar used by advanced navies endangers some cetaceans, including whales. In 2003 British and Spanish scientists suggested in Nature that sonar is connected to whale beachings and to signs that the beached whales have experienced decompression sickness. Responses in Nature the following year discounted the explanation.

Mass whale beachings occur in many species, mostly beaked whales that use echolocation for deep diving. The frequency and size of beachings around the world, recorded over the last 1,000 years in religious tracts and more recently in scientific surveys, has been used to estimate the population of various whale species by assuming that the proportion of the total whale population beaching in any one year is constant. Beached whales can give other clues about population conditions, especially medical conditions. For example, bleeding around ears, internal lesions, and nitrogen bubbles in organ tissue suggest that whales are in fact not immune to the bends.

Following public concern, the U.S. Defense department was ordered by the 9 Circuit Court to strictly limit use of its Low Frequency Active Sonar during peacetime. Attempts by the UK-based Whale and Dolphin Conservation Society to obtain a public inquiry into the possible dangers of the Royal Navy's equivalent (the "2087" sonar launched in December 2004) have failed as of 2008. The European Parliament has requested that EU members refrain from using the powerful sonar system until an environmental impact study has been carried out.

Other environmental disturbances

Other human activities have been suggested to adversely impact whale populations, such as the unregulated use of fishing gear which catches anything that swims into it, collisions with ships and propellers, and waste contaminants.

Whales in culture

Whales are frequently portrayed in literature as violent creatures that attack shipping and kill or eat sailors, despite overwhelming evidence to the contrary, particularly in literature written prior to the modern scientific study of the creatures, or in period literature. A common whale-themed plot device concerns mariners who are swallowed whole by a whale, and find themselves trapped alive in the creature's belly. In some instances, the victims of these encounters escape, often by causing the whale sufficient gastronomic distress that it is forced to expel them; in cases, the victim is doomed.

In religion

Portrayals of whales or whaling in religion include:

• The King James Version of the Bible mentions whales four times: "And God created great whales" (Genesis 1:21); "Am I a sea, or a whale, that thou settest a watch over me? (Job 7:12); "Thou art like a young lion of the nations, and thou art as a whale in the seas (Ezekiel 32:2); and "For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth" (Matthew 12:40).
  • The story of Jonah being swallowed by a whale also is mentioned in the Qur'an.
  • John Tavener's composition The Whale is based on the story of Jonah.
• Some cultures associate divinity with whales, such as among Ghanaians and Vietnamese, who occasionally hold funerals for beached whales, a throwback to Vietnam's ancient sea-based Austro-asiatic culture. The movie Whale Rider follows the trials of a girl named Paikia, who lives in such a culture, the Maouri of New Zeeland.

In popular culture

Portrayals of whales or whaling in literature, film, and television include:

• A kenning in Beowulf refers to the sea as the "whale-road."
• Procopius mentions a whale, nicknamed Porphyrio by the Byzantines, who depleted fisheries in the Sea of Marmara.
• In A Thousand and One Nights, Sinbad and his crew rest and light fires on an island. When they are thrown in the sea, they realize they mistook a whale for land.
• A whaling voyage is the plot of Herman Melville's novel Moby-Dick. In the book, Melville classed whales as "a spouting fish with a horizontal tail", despite contemporaneous science suggesting otherwise. (His narrator acknowledged "the grounds upon which Linnaeus would fain have banished the whales from the waters" but writes that when he presented them to "my friends Simeon Macey and Charley Coffin, of Nantucket ... they united in the opinion that the reasons set forth were altogether insufficient. Charley profanely hinted they were humbug" (Chapter 32).) Melville's book is a classic of American literature: part adventure novel, part metaphysical allegory, and part natural history; in part it summarizes 19th century knowledge about the biology, ecology and cultural significance of the whale.
• In the children's novel The Adventures of Pinocchio and subsequent adaptations, Pinocchio and his father are swallowed by a whale.
• Lynn Cox's award-winning literary memoir, Grayson, tells of her teenage encounter with a whale.
• Alan Hovhaness wrote a piece for orchestra entitled And God Created Great Whales.
• The poet Heathcote Williams wrote a book-length polemical poem entitled Whale Nation, published in 1988. Packed with detailed research and scores of photographs, it was described by one commentator as, "an epic plea for the future of the whale." The BBC television version was characterized as, "a hymn to the beauty, majesty and intelligence of the largest mammals on earth, as well as a prayer for their protection . . . Whale Nation became the most powerful argument for the newly instigated worldwide ban on whaling, and for a moment, back in 1988, it seemed as if a shameful chapter in human history might finally be drawing to a close."
• Festivals celebrating whales have sprung in both Sitka and Kodiak Alaska. They feature speakers on marine biology and celebrate the creatures with art, music, whale watching cruises, and symposia.
• Jacob M. Appel's "Dyads" recounts a woman's extra-martial affair during a whale-watching expedition.
• The Decemberists song "The Mariner's Revenge Song" concerns two sailors (one an older whaling ship captain and the other a young privateer) trapped together in a whale's belly, the latter seeking to kill the other to avenge his mother's death. At the time the privateer was preparing to attack the whaling ship, the whale in question attacked and sank both ships, eating all crew members of both ships.
• In the British series Hitchhiker's Guide to the Galaxy a whale, alongside a bowl of petunias, is created by the use of the Infinite Improbability Drive.
• In the film Star Trek IV, the Enterprise crew saves the world of the future by transporting two whales from our time to theirs.
• In the film Finding Nemo, a whale captures the characters Marlin and Dory. The whale transports them (in its mouth) to Sydney Harbour. Once there, it assists them in escaping via its blowhole.
• In the National Geographic Channel program "Extraterrestrial", in a moon called Blue Moon, its largest flying creatures are gargantuan whale-like creatures called Skywhales.
• Julian Lennon's film Whaledreamers is about the Mirning tribe of Australia whose culture centers around the whale.
• Whale Wars is a reality television series on Animal Planet that follows the trials and tribulations of the Sea Shepherd Conservation Society, an anti-whaling activist group currently fighting against Japanese whaling in the Southern Ocean, aboard the MV Steve Irwin and stars its founder Paul Watson.

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References

1. http://www.acsonline.org/education/taxonomy.html
2. Northeastern Ohio Universities Colleges of Medicine and Pharmacy. "Whales Descended From Tiny Deer-like Ancestors". ScienceDaily. Retrieved 2007-12-21.
3. Dawkins, Richard (2004). The Ancestor's Tale. Boston: Houghton Mifflin Company. ISBN 0-618-00583-8. {{cite book}}: Text "The Ancestor's Tale, A Pilgrimage to the Dawn of Life]]" ignored (help)
4. "How whales learned to swim". BBC News. 2002-05-08. Retrieved 2006-08-20.
5. "Hunting lance from 1800s found in whale". Retrieved 2007-06-14.
6. "Bowhead Whales May Be the World's Oldest Mammals". 2008-02-15. Retrieved 2008-03-25.
7. George, J.C.; et al. (1999). "Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization". Can. J. Zool. 77 (4): 571–580. doi:10.1139/cjz-77-4-571. {{cite journal}}: Explicit use of et al. in: |author= (help)
8. "Common Characteristics of Whale Teeth" here
9. "Anatomy of a Whale's Ears". Retrieved 2006-09-14.
10. "How is that whale listening?". Retrieved 2008-02-04.
11. "Table of sound decibel levels". Retrieved 2006-09-14.
12. "Milk". Modern Marvels. Season 14. 2008-01-07. The History Channel.
13. ^ Siebert, Charles (July 8, 2009). "Watching Whales Watching Us". New York Times Magazine. Cite error: The named reference "wwwu" was defined multiple times with different content (see the help page).
14. http://www.whaling.jp/english/history.html
15. Whale. Microsoft Encarta Online Encyclopedia 2009.
16. "Sonar may cause Whale deaths". BBC News. 2003-10-08. Retrieved 2006-09-14.
17. Piantadosi CA, Thalmann ED (2004-04-15). "Pathology: whales, sonar and decompression sickness". Nature. 428 (6894): 716–718. PMID 15085881.
18. Troubled Waters, London Independent, 20 September 2008

Further reading

• Carwardine, M., Whales, Dolphins and Porpoises, Dorling Kindersley, 2000. ISBN 0-7513-2781-6
• Williams, Heathcote, Whale Nation, New York, Harmony Books, 1988. ISBN 9780517569320

External links

• WikiAnswers: questions and answers about whales
• Whale Evolution
• Greenpeace work defending whales
• Save the Whales, founded in 1977
• AquaNetwork Marine Mammal Project
• Oldest whale fossil confirms amphibious origins
• Research on dolphins and whales from Science Daily
• Whale and Dolphin Conservation Society - latest news and information on whales and dolphins
• The Oceania Project - Caring for whales and dolphins
• Whales Tohorā Exhibition Minisite from the Museum of New Zealand Te Papa Tongarewa
• Whales in Te Ara the Encyclopedia of New Zealand
• Orca and other whales video at Squid Force
• www.whales.org.za Whales information portal
• World Wide Fund for Nature (WWF) - information on whales, dolphins, and porpoises
• Whale Trackers - An online documentary series about whales, dolphins and porpoises

• Articles with specifically marked weasel-worded phrases from March 2009
• Cetaceans