Tusk
Tusks are elongated, continuously growing front teeth, usually but not always in pairs, that protrude well beyond the mouth of certain mammal species. They are most commonly canines, as with warthogs, pig, and walruses, or, in the case of elephants and narwhals, elongated incisors. In most tusked species both the males and the females have tusks although the males are larger. Tusks are generally curved, though the narwhal's sole tusk is straight and has a helical structure. In the elephant, the tusks were originally second incisors. Continuous growth is enabled by formative tissues in the apical openings of the roots of the teeth.[1][2]
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[edit] Uses
Tusks have a variety of uses depending on the animal. Social displays of dominance, particularly among males, are common, as is their use in defense against attackers. Elephants use them as digging and boring tools. Walruses use them to grip on ice and to haul out on ice.[3] The presence of tusks in only the male narwhals suggests that for these whales it is a secondary sexual characteristic.[4]
Tusks are used by humans to produce ivory, which is used in artifacts and jewelry, and formerly in other items such as piano keys. Consequently, many tusk bearing species have been hunted commercially and several are endangered. The ivory trade has been severely restricted by the United Nations Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
[edit] See also
- Fang, a long canine tooth (in mammals)
- Ivory trade
- Sugar Mountain Farm, Pastured pig farm with large boars
- Tusk, a album by Fleetwood Mac
[edit] References
- ^ "Tusk". The Oxford English Dictionary. 2010. http://www.oed.com/.
- ^ Konjevic, D.; Kierdorf, U.; Manojlovic, L.; Severin, K.; Janicki, Z.; Slavica, A.; Reindl, B.; Pivac, Igor (4 April 2006). "The spectrum of tusk pathology in wild boar (Sus scrofa L.) from Croatia". Veterinarski Arhiv 76 (suppl.) (S91–S100). http://www.vef.hr/vetarhiv/papers/2006-76-7-12.pdf. Retrieved 9 January 2011.
- ^ Fay, F.H. (1985). "Odobenus rosmarus". Mammalian Species 238 (238): 1–7. doi:10.2307/3503810. http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/default.html.
- ^ "Monodon monoceros". Fisheries and Aquaculture Department: Species Fact Sheets. Food and Agriculture Organization of the United Nations. http://www.fao.org/fi/website/FIRetrieveAction.do?dom=species&fid=2742. Retrieved 2007-11-20.
