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The tail is the section at the rear end of certain kinds of
animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...
s’ bodies; in general, the term refers to a distinct, flexible appendage to the
torso The torso or trunk is an anatomical term for the central part, or the core, of the body of many animals (including humans), from which the head, neck, limbs, tail and other appendages extend. The tetrapod torso — including that of a hu ...
. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and
bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s. While tails are primarily a feature of vertebrates, some
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...
s including scorpions and
springtail Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called ...
s, as well as
snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class ...
s and slugs, have tail-like appendages that are sometimes referred to as tails. Tailed objects are sometimes referred to as "caudate" and the part of the body associated with or proximal to the tail are given the adjective "caudal".


Function

Animal tails are used in a variety of ways. They provide a source of locomotion for
fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...
and some other forms of marine life. Many land animals use their tails to brush away flies and other biting insects. Most
canine Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...
s use their tails to comunicate mood and intention . Some species, including cats and
kangaroo Kangaroos are four marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern ...
s, use their tails for balance; and some, such as monkeys and opossums, have what are known as
prehensile tail A prehensile tail is the tail of an animal that has adapted to grasp or hold objects. Fully prehensile tails can be used to hold and manipulate objects, and in particular to aid arboreal creatures in finding and eating food in the trees. If the t ...
s, which are adapted to allow them to grasp tree branches. Tails are also used for social signaling. Some
deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...
species flash the white underside of their tails to warn other nearby deer of possible danger, beavers slap the water with their tails to indicate danger, and canids (including domestic dogs) indicate
emotion Emotions are mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is currently no scientific consensus on a definitio ...
s through the positioning and movement of their tails. Some species' tails are armored, and some, such as those of scorpions, contain venom. Some species of lizard can detach ("cast") their tails from their bodies. This can help them to escape predators, which are either distracted by the wriggling, detached tail or left with only the tail while the lizard flees. Tails cast in this manner generally grow back over time, though the replacement is typically darker in colour than the original and contains only cartilage, not bone. Various species of rat demonstrate a similar function with their tails, known as degloving, in which the outer layer is shed in order for the animal to escape from a predator. Most birds' tails end in long feathers called
rectrices Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
. These feathers are used as a rudder, helping the bird 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 A lyrebird is either of two species of ground-dwelling Australian birds that compose the genus ''Menura'', and the family Menuridae. They are most notable for their impressive ability to mimic natural and artificial sounds from their environm ...
, and most notably peafowl—modified tail feathers play an important role in
courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
displays. The extra-stiff tail feathers of other species, including woodpeckers and
woodcreeper The woodcreepers (Dendrocolaptinae) comprise a subfamily of suboscine passerine birds endemic to the Neotropics. They have traditionally been considered a distinct family Dendrocolaptidae, but most authorities now place them as a subfamily o ...
s, allow them to brace themselves firmly against tree trunks. The tails of grazing animals, such as
horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
s, are used both to sweep away insects and positioned or moved in ways that indicate the animal's physical or emotional state.


Human tails

In humans,
tail bud In humans and other mammals, the caudal cell mass (also tail bud or caudal eminence in humans) is the aggregate of undifferentiated cells at the caudal end on the spine. The caudal end of the spinal cord first begins to form after primary neurula ...
refers to the part of the embryo which develops into the end of the spine. However, this is not a tail. Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels, muscles, and nerves, but this is regarded as an abnormality rather than a vestigial true tail, even when such an appendage is located where the tail would be expected. Fewer than 40 cases have been reported of infants with "true tails" containing the caudal vertebrae, a result of atavism. Humans have a "tail bone" (the coccyx) attached to the pelvis; it comprises fused vertebrae, usually four, at the bottom of the vertebral column. It does not normally protrude externally - humans are an '' acaudal'' (or ''acaudate'') species (i.e., tailless).


Gallery

File:Cub Stalks Tail.jpg, Lion (''Panthera leo'') File:Scorpion tail.jpg, Scorpion File:Pig tail DSC03974.jpg, Pig (''Sus domestica'') File:Queue glyptodon museum dijo.jpg, Glyptodon (''Glyptodon asper'') File:Lactoria cornuta (cola).006 - Aquarium Finisterrae.JPG, Longhorn cowfish (''Lactoria cornuta'') File:La Palmyre 041-crop.jpg, Grévy's zebra (''Equus grevyi'') File:Alligator Tail.jpg, American alligator (''Alligator mississipiensis'') File:Flusspferd Backstage.JPG,
Hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two exta ...
(''Hippopotamus amphibius'')


See also

*
Empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...
, the tail of an aircraft * Rump (animal)


References


External links

* {{Commons category-inline, Tails Animal anatomy