World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0000033777
Reproduction Date:

Title: Whale  
Author: World Heritage Encyclopedia
Language: English
Subject: Marine mammal, Ocean fisheries, Wild fisheries, Mammal, Biology/Previous articles
Publisher: World Heritage Encyclopedia


Temporal range: 50–0Ma
Eocene – Recent
North Atlantic right whales, mother and calf
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass: Eutheria
Order: Cetacea

Whale (origin baleen. This suborder includes the blue whale, the humpback whale, the bowhead whale and the minke whale. All cetaceans have forelimbs modified as fins, a tail with horizontal flukes, and nasal openings (blowholes) on top of the head.

Whales range in size from the blue whale, the largest animal known to have ever existed,[2] at 30 m (98 ft) and 180 tonnes (180 long tons; 200 short tons), to pygmy species such as the pygmy sperm whale at 3.5 m (11 ft). Whales inhabit all the world's oceans and number in the millions, with annual population growth rate estimates for various species ranging from 3% to 13%.[3] Whales are long-lived, humpback whales living for up to 77 years, while bowhead whales may live for more than a century.

Human hunting of whales from the seventeenth century until 1986 radically reduced the populations of some whale species.

Whales play a role in creation myths, for example among the Inuit, and they are revered by coastal people in countries such as Ghana and Vietnam.


Cetaceans are divided into two suborders:

  • The largest suborder, Mysticeti (baleen whales), is characterized by the presence of baleen, a sieve-like structure in the upper jaw made of keratin, which it uses to filter plankton from the water.
  • Odontoceti (toothed whales) bear sharp teeth for hunting. Odontoceti includes dolphins and porpoises. If they were not considered to be whales, this would mean that the informal grouping 'whale' is not a clade.

Cetaceans and [4]


Ambulocetus natans – a primitive cetacean

All cetaceans, including whales, dolphins, and porpoises, are descendants of land-dwelling mammals of the Artiodactyl order (even-toed ungulates). Both are related to the Indohyus, an extinct semi-aquatic deer-like ungulate, from which they split approximately 54 million years ago.[5][6] These primitive cetaceans first took to the sea approximately 50 million years ago and became fully aquatic by 5–10 million years later.[7] Their features became adapted for living in the marine environment. Major anatomical changes include streamlining of the body, the migration of the nasal openings toward the top of the cranium, the shrinking and eventual disappearance of the hind limbs, the modification of the forelimbs into flippers, and the growth of flukes on the tail.


As with all mammals, whales breathe air, are warm-blooded, nurse their young with milk from mammary glands, and have body hair.[8] Beneath the skin lies a layer of fat called blubber, which stores energy and insulates the body. Whales have a spinal column, a vestigial pelvic bone, and a four-chambered heart. Typically, the neck vertebrae are fused, an adaptation trading flexibility for stability during swimming.[9][10]


Features of a blue whale

Whales breathe via blowholes; baleen whales have two and toothed whales have one. These are located on the top of the head, allowing the animal to remain almost completely submerged while breathing. Breathing involves expelling stale air (which is warm and moist), as well as some mucus and excess water from the blowhole, forming an upward, steamy spout, followed by inhaling fresh air into the lungs.[11] Spout shapes differ among species, which facilitates identification.


The body shape is fusiform and the modified forelimbs, or fins, are paddle-shaped. The end of the tail is composed of two flukes, which propel the animal by vertical movement, as opposed to the horizontal movement of a fish tail. Although whales do not possess fully developed hind limbs, some (such as sperm whales and baleen whales) possess discrete rudimentary appendages, which may contain feet and digits. Most species have a dorsal fin.[12][13]

During March 2014 in Japan a bottle-nosed dolphin with hind fins about as large as a human hand, was captured.[14]


Toothed whales, such as the sperm whale, possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show.[15]

Instead of teeth, baleen whales have a row of baleen plates on the upper side of their jaws that resemble the teeth of a comb.


The whale ear has specific adaptations to the marine environment. In humans, the middle ear works as an impedance equalizer 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 the outer ear to the middle ear, whales receive sound through the throat, from which it passes through a low-impedance fat-filled cavity to the inner ear.[16] The whale ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater.[17]

Life history and behavior


Males are called 'bulls', females, 'cows' and all newborns, 'calves'. Most species do not maintain fixed reproductive partnerships. Females have several mates each season.[18][19]

The female usually delivers a single calf, which is birthed tail-first to minimize the risk of drowning. Whale cows nurse by squirting milk into the mouths of their young. This milk is so rich in fat that it has the consistency of toothpaste.[18] In many species, nursing continues for more than a year and is associated with a strong bond between mother and calf. Reproductive maturity typically occurs at seven to ten years. This mode of reproduction produces few offspring, but increases the survival probability of each one.


Whales are known to teach, learn, cooperate, scheme, and even grieve.[20] The neocortex of many species of whale is home to elongated spindle neurons that, prior to 2007, were known only in hominids.[21] In humans these cells are involved in social conduct, emotions, judgment, and theory of mind.[22] Whale spindle neurons are found in areas of the brain that are homologous to where they are found in humans, suggesting that they perform a similar function.[23]


Photo of humpback whale with most of its body out of the water and its pectoral fins extended
A humpback whale breaching

Unlike most animals, whales are conscious breathers. All mammals sleep, but whales cannot afford to become unconscious for long because they may drown. While knowledge of sleep in wild cetaceans is limited, toothed cetaceans in captivity have been recorded to sleep with one side of their brain at a time, ostensibly so that they may swim, breathe consciously, avoid both predators and social contact during their period of rest. It is thought that only one hemisphere of the whale's brain sleeps at a time, so that they rest, but are never completely asleep.[24]

A 2008 study found that wild sperm whales (Physeter macrocephalus) sleep in vertical postures just under the surface in passive shallow 'drift-dives', generally during the day, during which whales do not respond to passing vessels unless they are in contact, leading to the suggestion that whales possibly sleep during such dives.[25]

Surfacing behavior

Many whales exhibit behaviors that expose large parts of their bodies to the air, such as breaching and tail slapping.


Sounding is a term used for whales diving. Typically it is only used for longer dives. Before sounding, whales typically stay close to the surface for a series of short, shallow dives while building their oxygen reserves. They then make a sounding dive.


Whale lifespans vary among species and are not well characterized. Whaling left few older individuals to observe directly. R.M. Nowak of Johns Hopkins University estimated that humpback whales may live as long as 77 years.[26] In 2007, a nineteenth-century lance fragment was found in a bowhead whale off Alaska, which suggests the individual could be between 115 and 130 years old.[27] Aspartic acid racemization in the whale eye, combined with a harpoon fragment, indicated an age of 211 years for another male, which, if true, would make bowheads the longest-lived extant mammal species.[28][29] The accuracy of this age determination method has been questioned because racemization does not correlate well with other dating methods.[30]


Recording of Humpback Whales singing and Clicking.

Problems playing this file? See .
Some species, such as the humpback whale, communicate using melodic sounds, known as whale song. These sounds may be extremely loud, depending on the species. Sperm whales only have been heard making clicks, while toothed whales (Odontoceti) use echolocation that may generate approximately 20,000 watts of sound (+73 dBm or +43 dBw)[31] and be heard for many miles. Whale vocalization is likely to serve many purposes, including echolocation, mating, and identification.[32]

Captive whales occasionally have been known to mimic human speech. Scientists have suggested this indicates a strong desire on behalf of the whales to communicate with humans, as whales have a very different vocal mechanism, so producing human speech likely takes considerable effort.[33]


"Whale pump" - the role played by whales in nutrient recycling in the oceans

Whales are considered as "marine ecosystem engineers" for the following reasons:[34]

  • Whales are major consumers of fish and oceanic invertebrates.
  • Whales act as reservoirs of nutrients, such as iron and nitrogen, and they recycle them both horizontally and vertically in the water column.
  • Whale detritus provides energy and habitat for deep sea organisms.


Whales generally are classed as predators. Their food ranges from microscopic plankton to very large animals.

Toothed whales eat fish and squid, which they hunt by the use of echolocation. Killer whales sometimes eat other marine mammals, including whales.

Baleen whales, such as humpbacks and blues, mainly eat krill when feeding in the higher latitudes (such as the Southern Ocean). They take in enormous amounts of seawater that they expel through their baleen plates; the krill in the seawater are retained on the plates and then swallowed.[18] Whales do not drink seawater. They extract water indirectly from their food by metabolizing fat.[18]

Whale pump

A 2010 study considered whales to be a positive influence to the productivity of ocean fisheries, in what has been termed a "whale pump." Whales carry nutrients such as nitrogen from the depths back to the surface. This functions as an upward biological pump, reversing an earlier presumption that whales accelerate the loss of nutrients to the bottom. This nitrogen input in the Gulf of Maine is "more than the input of all rivers combined" emptying into the gulf, some 23,000 metric tons each year.[35][36] Whales defecate at the oceans surface and this excrement is important for fisheries because it is rich in iron and nitrogen. The whale feces are liquid and instead of sinking, they stay at the surface where phytoplankton feed off it. [37]

Whale fall

Upon death, whale carcasses fall to the deep ocean and being massive, with body weights of the range 30 to 160 tonnes (30,000 to 160,000 kg), provide a substantial habitat for marine creatures. Evidence of whale falls in present day and fossil records shows that deep sea whale falls support a rich assemblage of creatures, with a global diversity of 407 species as per Smith & Baco (2003), comparable to other neritic biodiversity hotspots, such as cold seeps and hydrothermal vents.[38]

Deterioration of whale carcasses happens though a series of three stages. Initially, moving organisms such as [38]

Interaction with humans


Dutch whalers near Spitsbergen, Abraham Storck, 1690
Map showing IWC non-members such as Canada and most Middle Eastern and African countries in white
World map of International Whaling Commission (IWC) members/non-members(member countries in blue)

Diagram showing the pre-whaling of 275,000, 1930s population of 30–40,000, mid-60s population of 650–2,000 and 1994 population of fewer than 5,000
World population graph of blue whales (Balaenoptera musculus)

Some species of large whales are listed as endangered by multinational organizations, such as CITES, as well as governments and advocacy groups. This status is due primarily to the impact of whaling. Whales have been hunted commercially since the seventeenth century for whale oil, meat, baleen, and ambergris (a perfume ingredient from the intestine of sperm whales).[39] More than two million whales were taken during the twentieth century,[40] and by the middle of that century, many populations were severely depleted.

The International Whaling Commission banned commercial whaling in 1986.[41] The ban is not absolute, however, and some whaling continues under the auspices of scientific research[41] (sometimes not proved[42]) or aboriginal rights. Current whaling nations are Norway, Iceland, and Japan as well as the aboriginal communities of Siberia, Alaska, and northern Canada.


Several species of small whales are caught as bycatch while fishing 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.[43]

Naval sonar

Environmentalists speculate that advanced naval sonar endangers some cetaceans, including whales. In 2003, British and Spanish scientists suggested in Nature that the effects of sonar trigger whale beachings and they point to signs that such whales have experienced decompression sickness.[44] Responses in Nature the following year discounted the explanation.[45]

Mass beachings occur in many species, mostly [20]

Following public concern, the U.S. Defense department was ordered by the 9th 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) 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.

In fiction

The 1851 American novel, Moby-Dick by Herman Melville concerns a vexed captain's hunt for a gigantic white whale. Rudyard Kipling's 1902 Just So Stories includes the tale of "How the Whale got his Throat".[46] The film Whale Rider directed by Niki Caro has a Maori girl ride a whale in her quest to be a suitable heir to the chiefship.[47] An enormous whale called Monstro is the final antagonist featured in Walt Disney's 1940 animated film Pinocchio.

In mythology

Whale weather-vane atop the Nantucket Historical Association Whaling Museum displaying a sperm whale

Whales were little understood for most of human history as little of their lives could be seen from the surface of the ocean.[48] Many cultures, even those that have hunted them, hold whales in awe and feature them in their mythologies. In China, Yu-kiang, a whale with the hands and feet of a human was said to rule the ocean.[49] In the [49]

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.[54][55][56][57]

The Bible mentions whales in Genesis 1:21, Job 7:12, Ezekiel and 32:2. The "sea monsters" in Lamentations 4:3 have been taken by some commentators to refer to marine mammals, in particular whales, although most modern versions use the word "jackals" instead.[58] The story of Jonah being swallowed by a "big Fish" is told both in the Qur'an and in the Bible.[59] The Old Testament contains the Book of Jonah and in the New Testament, Jesus mentions this story in Matthew 12:40.[60]

The engraving by William van der Gouwen shows a 20 m (65.6 ft) long whale, stranded on the Dutch coast between Scheveningen and Katwijk on 3 February 1598

In music

And God Created Great Whales, written in 1970 by American composer Alan Hovhaness, is a work for orchestra and whale songs, including the recorded sounds of humpback, bowhead, and killer whales.[61] The song "Il n'y a plus rien", from French singer-songwriter Léo Ferré's eponymous album (1973), is an example of biomusic that begins and ends with recorded whale songs mixed with a symphonic orchestra and his voice.

See also


  1. ^ Brown, Lesley, ed. (2007). Shorter Oxford English Dictionary II (Sixth ed.). Oxford: Oxford University press. p. 3611. 
  2. ^ "What is the biggest animal ever to exist on Earth?". How Stuff Works. Retrieved 2007-05-29. 
  3. ^ "Whale Population Estimates". International Whaling Commission. March 2010. Retrieved March 2010. 
  4. ^ Anon (25 January 2005). "Scientists find missing link between the whale and its closest relative, the hippo". Retrieved 6 May 2010. 
  5. ^ Northeastern Ohio Universities Colleges of Medicine and Pharmacy. "Whales Descended From Tiny Deer-like Ancestors". ScienceDaily. Retrieved 2007-12-21. 
  6. ^  
  7. ^ "How whales learned to swim". BBC News. 8 May 2002. Retrieved 2006-08-20. 
  8. ^ "Whales". Retrieved 2012-05-17. 
  9. ^ "Beluga Whale". 2012-06-27. Retrieved 2013-08-12. 
  10. ^ "About Whales". 2009-06-26. Retrieved 2013-08-12. 
  11. ^ Whales Don’t Spray Water Out of Their Blowholes
  12. ^ "Whales". Retrieved 2013-08-12. 
  13. ^ Amazing Facts
  14. ^ [1] [2]
  15. ^ "Common Characteristics of Whale Teeth". Retrieved 18 July 2014. 
  16. ^ "How is that whale listening?". Retrieved 4 February 2008. 
  17. ^ Nummela, Sirpa.; Thewissen, J.G.M; Bajpai, Sunil; Hussain, Taseer; Kumar, Kishor (2007). "Sound transmission in archaic and modern whales: Anatomical adaptations for underwater hearing". The Anatomical Record 290 (6): 716–733.  
  18. ^ a b c d "Blue Whale". Discovery Channel Blue Ocean.
  19. ^ "Milk". Modern Marvels. Season 14. 2008-01-07. The History Channel.
  20. ^ a b Siebert, Charles (8 July 2009). "Watching Whales Watching Us". New York Times Magazine. 
  21. ^ Watson, K.K.; Jones, T.K.; Allman, J.M. (2006). "Dendritic architecture of the Von Economo neurons". Neuroscience 141 (3): 1107–1112.  
  22. ^ Allman, John M.; Watson, Karli K.; Tetreault, Nicole A.; Hakeem, Atiya Y. (2005). "Intuition and autism: a possible role for Von Economo neurons". Trends Cogn Sci 9 (8): 367–373.  
  23. ^ Hof, Patrick R.; Van Der Gucht, Estel (2007). "Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae)". The Anatomical Record 290 (1): 1–31.  
  24. ^ Anon. "Do whales and dolphins sleep?". How Stuff Works. Discovery Communications. Retrieved 14 February 2010. 
  25. ^ Miller, P. J. O.; Aoki, K.; Rendell, L. E.; Amano, M. (2008). "Stereotypical resting behavior of the sperm whale". Current Biology 18 (1): R21–R23.  
  26. ^ Anon (2005). "Humpback Whale". Animal Infor. Animal Info. Retrieved 25 February 2010. 
  27. ^ Conroy, Erin (June 2007). "Netted whale hit by lance a century ago". Associated Press. Retrieved 2009-10-05. 
  28. ^ "Bowhead Whales May Be the World's Oldest Mammals". 15 February 2008. Retrieved 2008-03-25. 
  29. ^ George, J.C.; Bada, Jeffrey; Zeh, Judith; Scott, Laura; Brown, Stephen E.; O'Hara, Todd; Suydam, Robert (1999). "Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization". Can. J. Zool. 77 (4): 571–580.  
  30. ^ Brignole, Edward; McDowell, Julie. "Amino Acid Racemization". Today's chemist at work. American Chemical Society. Retrieved 25 February 2010. 
  31. ^ dBm – dBw Watts conversion chart,
  32. ^ "Cetacean Curriculum – A teacher’s guide to introducing and using whales, dolphins, & porpoises in the classroom" (PDF). American Cetacean Society. 28 November 2004. Retrieved 20 December 2013. Sound production in cetaceans is a complex phenomenon not fully understood by scientists. 
  33. ^ Nick Collins (2012-10-22). "Whale learns to mimic human speech". London:  
  34. ^ Roman, Joe ; Estes, James A.; Morissette, Lyne; Smith, Craig ; Costa, Daniel; McCarthy, James; Nation, J.B.; Nicol, Stephen; Pershing, Andrew & Smetacek, Victor (2014). "Whales as marine ecosystem engineers". Frontiers in Ecology and the Environment (Ecological Society of America).  
  35. ^ "Whale poop pumps up ocean health". ScienceDaily. October 12, 2010. Retrieved 2011-11-18. 
  36. ^ Roman J, McCarthy JJ (2010). Roopnarine, Peter, ed. "The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin". PLoS ONE 5 (10): e13255.  
  37. ^ "Whale poo important for ocean ecosystems". Australian Geographic. 26 May 2014. Retrieved 18 November 2014. 
  38. ^ a b Smith, Craig R. & Baco, Amy R. (2003). "Ecology of Whale Falls at the Deep-Sea Floor". Oceanography and Marine Biology: an Annual Review (Taylor & Francis) 41: 311–354. Retrieved 23 August 2014. 
  39. ^ Japan Whaling Assoc. -History of Whaling. Retrieved on 2011-11-18.
  40. ^ Desonie, Dana (2008). Polar Regions: Human Impacts. Infobase Publishing. p. 154.  
  41. ^ a b Anon. "Revised Management Scheme Information on the background and progress of the Revised Management Scheme (RMS)". International Whaling Commission. Retrieved 14 March 2010. 
  42. ^ Whaling on trial: Vindication!. (23 December 2010). Retrieved on 2011-11-18.
  43. ^ The Tuna-Dolphin Issue - SWFSC
  44. ^ Kirby, Alex (8 October 2003). "Sonar may cause Whale deaths". BBC News. Retrieved 2006-09-14. 
  45. ^ Piantadosi CA, Thalmann ED (15 April 2004). "Pathology: whales, sonar and decompression sickness". Nature 428 (6894): 716–718.  
  46. ^ Kipling, Rudyard. "How the Whale got his Throat". Retrieved 30 November 2013. 
  47. ^ French, Philip; Bradshaw, Peter (2003). "Whale Rider". (two reviews). The Guardian. Retrieved 30 November 2013. 
  48. ^  
  49. ^ a b c Siebert, Charles (2011). NRDC The Secret World of Whales. illustrated by Molly Baker (illustrated ed.). Chronicle Books. pp. 15–16.  
  50. ^   (see also Seclusion of girls at puberty)
  51. ^ Anon. "Whales". Tinirau education resource. Retrieved 14 February 2010. 
  52. ^ Heimlich, Sara; Boran, James (2001). Killer Whales. Voyageur Press. p. 7.  
  53. ^ Anon. "Whale Mythology from around the World". The Creative Continuum. Retrieved 14 February 2010. 
  54. ^ "Whale funeral draws 1000 mourners in Vietnam". Sydney Morning Herald. AFP. 14 April 2003. Retrieved 15 April 2011. 
  55. ^ "Thousand gather for whale's funeral in Vietnam". The Independent (London). Associated Press. 23 February 2010. Retrieved 15 April 2011. 
  56. ^ Viegas, Jennifer. "Thousands Mourn Dead Whale in Vietnam". Discovery News. Retrieved 15 April 2011. 
  57. ^ "Funeral for a Whale held at Apam". Ghana News Agency. GhanaWeb. Retrieved 15 April 2011. 
  58. ^ Lamentations 4:3 multiple versions and commentaries page
  59. ^ Quran 37:139–148
  60. ^ "Jonah 1-4 New International Version". Bible Gateway. Retrieved 30 December 2013. 
  61. ^ And God Created Great Whales (1970) for Orchestra and Whale Songs Artist direct (Retrieved 10 October 2007)

Further reading

  • Carwardine, M. (2000). Whales, Dolphins and Porpoises. Dorling Kindersley.  .

External links

  • Whale Evolution
  • Oldest whale fossil confirms amphibious origins
  • World Wide Fund for Nature (WWF) – information on whales, dolphins, and porpoises
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.