Tail

Tail

The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals and birds. While tails are primarily a feature of vertebrates, some invertebrates—including scorpions and springtails—have tail-like appendages.

Function

Animal tails are used in a variety of ways. They provide a source of locomotion for fish and some other forms of marine life. Many land animals use their tails to brush away flies and other biting insects. Some species, including cats and kangaroos, use their tails for balance, and some, such as New World monkeys and opossums, use their prehensile tails to grasp tree branches.

Tails are also used for social signaling. Some deer species flash the white underside of their tails to warn other nearby deer of possible danger, and canids (including domestic dogs) indicate emotions through the positioning of their tails. Evolutionary pressures have led to the development of armored tails in some species, and some, such as the tails of scorpions contain venom.

Some species of lizard can detach ("cast") their tails from their bodies. This can help them to escape from predators, which are either distracted by the wriggling detached tail, or left with only the tail while the rest of the lizard flees. Tails cast in this manner generally grow back over time, though the replacement is typically darker in color than the original.

The tails of most birds end in long feathers called rectrices. These feathers are used as a rudder, helping the bird to steer and maneuver in flight; they also help the bird to balance while it is perched. In some species—such as birds of paradise, lyrebirds and peacocks—modified tail feathers play an important role in courtship displays. The extra-stiff tail feathers of other species, including woodpeckers and woodcreepers, allow them to brace themselves firmly against tree trunks.

Human tails

Human embryos have a tail that measures about one-sixth of the size of the embryo itself. As the embryo develops into a fetus, the tail is absorbed by the growing body. The developmental tail is thus a human vestigial structure. Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels, muscles, and nerves, although there have been a very few documented cases of tails containing cartilage or up to five vertebrae. Modern procedures allow doctors to eliminate the tail at delivery. Some of these tails may in fact be sacrococcygeal teratomas. The longest human tail on record belonged to a twelve-year-old boy living in what was then French Indochina, which measured 229 mm (9 inches). [cite web | title = Humans Evolved from Ape-like Ancestors | url = http://www.dimaggio.org/Eye-Openers/tails_in_humans.htm] A man named Chandre Oram, who was lives in West Bengal, a state in India, is famous because of his convert|13|in|mm|sing=on tail. It is not believed to be a true tail, however, but rather a case of spina bifida.

Humans have a tail bone (the coccyx) attached to the pelvis, in the same place which other mammals have tails. The tail bone is formed of fused vertebrae, usually four, at the bottom of the vertebral column. It doesn't protrude externally, but retains an anatomical purpose: providing an attachment for muscles like the gluteus maximus.

ee also

*Rump (croup)

External links

References


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  • Tail — Tail, n. [AS. t[ae]gel, t[ae]gl; akin to G. zagel, Icel. tagl, Sw. tagel, Goth. tagl hair. [root]59.] 1. (Zo[ o]l.) The terminal, and usually flexible, posterior appendage of an animal. [1913 Webster] Note: The tail of mammals and reptiles… …   The Collaborative International Dictionary of English

  • Tail — Saltar a navegación, búsqueda tail (que significa cola en inglés) es un programa de los sistemas tipo Unix, que muestra las últimas líneas de uno o más archivos de texto. tail imprimirá por defecto a la salida estándar las últimas diez líneas de… …   Wikipedia Español

  • tail — (que significa cola en inglés) es un programa de los sistemas tipo Unix, que muestra las últimas líneas de uno o más archivos de texto. tail imprimirá por defecto a la salida estándar las últimas diez líneas de sus datos de entrada. Tanto las… …   Wikipedia Español

  • tail — 1 n [Anglo French, literally, cutting, from Old French, from taillier to cut, prune] 1: the condition of being limited or restricted by entailing a tenant in tail 2: entail (2) tail 2 adj: limited as to tenure see al …   Law dictionary

  • tail — tail1 [tāl] n. [ME < OE tægel, akin to OHG zagel < IE base * dek̑ , to tear, tear off > Sans saśā, fringe] 1. a) the rear end of an animal s body, esp. when forming a distinct, flexible appendage to the trunk b) such an appendage 2.… …   English World dictionary

  • tail — ► NOUN 1) the hindmost part of an animal, especially when extended beyond the rest of the body. 2) something extending downwards, outwards, or back like an animal s tail. 3) the rear part of an aircraft, with the tailplane and rudder. 4) the… …   English terms dictionary

  • Tail — утилита в UNIX, выводящая несколько (по умолчанию 10) последних строк из файла. Синтаксис tail [параметры] имя файла Ключ n <количество строк> (или просто <количество строк>) позволяет изменить количество выводимых строк: tail 20… …   Википедия

  • tail — tail  утилита в UNIX, выводящая несколько (по умолчанию 10) последних строк из файла. Синтаксис tail [параметры] имя файла Ключ n <количество строк> (или просто <количество строк>) позволяет изменить количество выводимых строк:… …   Википедия

  • Tail — Tail, v. t. 1. To follow or hang to, like a tail; to be attached closely to, as that which can not be evaded. [Obs.] [1913 Webster] Nevertheless his bond of two thousand pounds, wherewith he was tailed, continued uncanceled, and was called on the …   The Collaborative International Dictionary of English

  • Tail — Tail, n. [F. taille a cutting. See {Entail}, {Tally}.] (Law) Limitation; abridgment. Burrill. [1913 Webster] {Estate in tail}, a limited, abridged, or reduced fee; an estate limited to certain heirs, and from which the other heirs are precluded;… …   The Collaborative International Dictionary of English

  • Tail — Tail, a. (Law) Limited; abridged; reduced; curtailed; as, estate tail. [1913 Webster] …   The Collaborative International Dictionary of English

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