Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most amniotes (mammals, reptiles, birds).

Some invertebrates such as beetles and spiders have somewhat similar fine hooked structures at the end of the leg or tarsus for gripping a surface as the creature walks. Crabs', lobsters' and scorpions' pincers, or more formally, their chelae, are sometimes called claws.

A true claw is made of hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense, and grooming, in those and other species.

Similar appendages that are flat and do not come to a sharp point are called nails instead. Claw-like projections that do not form at the end of digits, but spring from other parts of the foot are properly named spurs.[1]

Cat claw closeup
A domestic cat's retractable claw in protracted position

Tetrapods

In tetrapods, claws are made of keratin and consist of two layers. The unguis is the harder external layer, which consists of keratin fibers arranged perpendicular to the direction of growth and in layers at an oblique angle. The subunguis is the softer, flaky underside layer whose grain is parallel to the direction of growth. The claw grows outward from the nail matrix at the base of the unguis and the subunguis grows thicker while travelling across the nail bed. The unguis grows outward faster than the subunguis to produce a curve and the thinner sides of the claw wear away faster than their thicker middle, producing a more or less sharp point. Tetrapods use their claws in many ways, commonly to grasp or kill prey, to dig and to climb and hang.

Mammals

Katzenkralle
A claw sheath from a cat

All Carnivora have claws, which vary considerably in length and shape. Claws grow out of the third phalanges of the paws and are made of keratin. Many predatory mammals have protractile claws that can partially hide inside the animal's paw, especially the cat family, Felidae, almost all of whose members have fully protractible claws. Outside of the cat family, retractable claws are found only in certain species of the Viverridae (and the extinct Nimravidae).[2] A claw that is retractable is protected from wear and tear.

Most cats and dogs also have a dewclaw on the inside of the front paws. It is much less functional than the other claws but does help the cats to grasp prey. Because the dew claw does not touch the ground, it receives less wear and tends to be sharper and longer.

A nail is homologous to a claw but is flatter and has a curved edge instead of a point. A nail that is big enough to bear weight is called a "hoof". (Nevertheless, one side of the cloven-hoof of artiodactyl ungulates may also be called a claw).

Every so often, the growth of claws stops and restarts, as does hair. In a hair, this results in the hair falling out and being replaced by a new one. In claws, this results in an abscission layer, and the old segment breaks off. This process takes several months for human thumbnails. Cats are often seen working old unguis layers off on wood or on boards made for the purpose. Ungulates' hooves wear or self-trim by ground contact. Domesticated equids (horses, donkeys and mules) usually need regular trimming by a farrier, as a consequence of reduced activity on hard ground.

Primates

Primate nails consist of the unguis alone, as the subunguis has disappeared. With the evolution of grasping hands and feet, claws are no longer necessary for locomotion, and instead most digits exhibit nails. However, claw-like nails are found in small-bodied callitrichids on all digits except the hallux or big toe. A laterally flattened grooming claw, used for grooming, can be found on the second toe in living strepsirrhines, and the second and third in tarsiers. Aye-ayes have functional claws on all other digits except the hallux, including a grooming claw on the second toe.[3] Less commonly known, a grooming claw is also found on the second pedal digit of night monkeys (Aotus), titis (Callicebus), and possibly other New World monkeys.[4]

Reptiles

Therizinosaurus claw
At just under a meter, the claws of Therizinosaurus are among the largest recorded.
Grenn lizzard
Using its claws for anchoring, a green lizard basks.

Most reptiles have well-developed claws. Most lizards have toes ending in stout claws, forming from the last scale on the toe.[5] In snakes, feet and claws are absent, but in many boids such as Boa constrictor, remnants of highly reduced hind-limbs emerge with a single claw as "spurs" on each side of the anal opening.

Lizard claws are used as aids in climbing, and in holding down prey in carnivorous species.

Birds

A talon is the claw of a bird of prey, its primary hunting tool.[6] The talons are very important; without them, most birds of prey would not be able to catch their food. Some birds also use claws for defensive purposes. Cassowaries use claws on their inner toe (digit II) for defence, and have been known to disembowel people.[7][8] All birds however have claws, which are used as general holdfasts and protection for the tip of the digits.

The hoatzin and turaco are unique among extant birds in having functional claws on the thumb and index finger (digit I and II) on the forelimbs as chicks, allowing them to climb trees until the adult plumage with flight feathers develop.[9][10] However, several birds have a claw- or nail-like structure hidden under the feathers at the end of the hand digits, notably ostriches, emus, ducks, geese and kiwis.[11]

Amphibians

The only amphibians to bear claws are the African clawed frogs. Claws appear to have evolved separately in the amphibian and amniote line.[12]

Arthropods

The scientifically correct term for the "claw" of an arthropod, such as a lobster or crab, is a chela (plural chelae). Legs bearing a chela are called chelipeds. Chelae are also called pincers.

See also

References

  1. ^ Rand, A.L. (1954). "On the Spurs on Birds' Wings" (PDF). The Wilson Bulletin. 66 (2): 127–134. Retrieved 16 November 2012.
  2. ^ Anton, Mauricio (1997). The Big Cats and Their Fossil Relatives. Columbia University Press. pp. 130-33. ISBN 978-0-231-10228-5.
  3. ^ Soligo, C.; Müller, A. E. (1999). "Nails and claws in primate evolution". Journal of Human Evolution. 36 (1): 97–114. doi:10.1006/jhev.1998.0263. PMID 9924135.
  4. ^ Maiolino, S.; Boyer, D. M.; Rosenberger, A. (2011). "Morphological Correlates of the Grooming Claw in Distal Phalanges of Platyrrhines and Other Primates: A Preliminary Study". The Anatomical Record. 294 (12): 1975–1990. doi:10.1002/ar.21498. PMID 22042603.
  5. ^ Alibardi, L. (2008). "Microscopic analysis of lizard claw morphogenesis and hypothesis on its evolution". Acta Zoologica. 89 (2): 169–178. doi:10.1111/j.1463-6395.2007.00312.x.
  6. ^ Fowler, D.W., Freedman, E.A., & Scannella, J.B. (2009). Pizzari, Tom (ed.). "Predatory Functional Morphology in Raptors: Interdigital Variation in Talon Size Is Related to Prey Restraint and Immobilisation Technique". PLoS ONE. 4 (11): e7999. doi:10.1371/journal.pone.0007999. PMC 2776979. PMID 19946365.CS1 maint: Multiple names: authors list (link)
  7. ^ Lumeij, J. T. (1987). "Avian clinical pathology. General considerations". Veterinary Quarterly. 9:3 (3): 249–254. doi:10.1080/01652176.1987.9694109. PMID 3314103.
  8. ^ Cho, Patricia; Brown, Rosanne; Anderson, Marilyn (1984-01-01). "Comparative gross anatomy of ratites". Zoo Biology. 3 (2): 133–144. doi:10.1002/zoo.1430030205. ISSN 1098-2361.
  9. ^ Fain, Matthew G.; Houde, Peter (2004). "Parallel radiations in the primary clades of birds" (PDF). Evolution. 58 (11): 2558–2573. doi:10.1554/04-235. PMID 15612298. Retrieved 2016-07-08.
  10. ^ Parker, W. K. (1891). "On the Morphology of a Reptilian Bird, Opisthocomus hoazin". Transactions of the Zoological Society of London. 13 (2): 43–89. doi:10.1111/j.1096-3642.1891.tb00045.x.
  11. ^ Sir Walter Lawry Buller (1888): A History of the Birds of New Zealand. London excerpt from Zealand Electronic Text Centre collection
  12. ^ Maddin, HC; Eckhart, L; Jaeger, K; Russell, AP; Ghannadan, M (2009). "The anatomy and development of the claws of Xenopus laevis (Lissamphibia: Anura) reveal alternate pathways of structural evolution in the integument of tetrapods". Journal of Anatomy. 214 (4): 607–19. doi:10.1111/j.1469-7580.2009.01052.x. PMC 2736125. PMID 19422431.

External links

Bagh nakh

The bagh nakh, vagh nakh, or vagh nakhya (Marathi: वाघनख / वाघनख्या, Hindi: बाघ नख, Urdu: باگھ نکھ‎, lit. tiger claw) is a claw-like weapon, originating from the Indian subcontinent, designed to fit over the knuckles or be concealed under and against the palm. It consists of four or five curved blades affixed to a crossbar or glove, and is designed to slash through skin and muscle. It is believed to have been inspired by the armament of big cats, and the term bagh nakh itself means tiger's claw in Hindi.

Bear claw (pastry)

A bear claw is a sweet, yeast-raised pastry, similar to a Danish, originating in the United States during the mid-1920s. A bear claw is usually filled with almond paste, and sometimes raisins, and often shaped in a semicircle with slices along the curved edge, or rectangular with partial slices along one side. As the dough rises, the sections separate, evoking the shape of a bear's toes, hence the name.The name bear claw as used for a pastry is first attested in 1936. The phrase is more common in Western American English, and is included in the U.S. Regional Dialect Survey Results, Question #87, "Do you use the term 'bear claw' for a kind of pastry?"

Claw crane

A claw crane, toy crane or skill crane is a type of arcade game known as a merchandiser, commonly found in video arcades, supermarkets, restaurants, movie theaters, shopping malls, and bowling alleys.

Crab claw sail

The crab claw sail or, as it is sometimes known, Oceanic lateen or Oceanic sprit, is a triangular sail with spars along upper and lower edges. The crab claw sail is used in many traditional Austronesian cultures, as can be seen by the traditional paraw, proa, lakana, and tepukei.

Crowbar (tool)

A crowbar, also called a wrecking bar, pry bar or prybar, pinch-bar, or occasionally a prise bar or prisebar, colloquially, in Britain and Australia sometimes called a jimmy (also called jimmy bar or jemmy), gooseneck, or pig foot, is a tool consisting of a metal bar with a single curved end and flattened points, often with a small fissure on one or both ends for removing nails. It is also a class 1 lever. In Britain, Ireland, New Zealand, and Australia, due to the influence of American media "crowbar" may occasionally be used loosely for this tool, but it is still mainly used to mean a larger straighter tool, its original English meaning (see digging bar). The term jammy or jimmy most often refers to the tool when used for burglary.It is used as a lever either to force apart two objects or to remove nails. Crowbars are commonly used to open nailed wooden crates or pry apart boards. Crowbars can be used as any of the three lever classes but the curved end is usually used as a first-class lever, and the flat end as a second-class lever. In mining, crowbars are used to break and remove rock, but not as much in modern mining.

Cthulhu

Cthulhu () is a fictional cosmic entity created by writer H. P. Lovecraft and first introduced in the short story "The Call of Cthulhu", published in the American pulp magazine Weird Tales in 1928. Considered a Great Old One within the pantheon of Lovecraftian cosmic entities, the creature has since been featured in numerous popular culture references. Lovecraft depicts Cthulhu as a gigantic entity worshipped by cultists. Cthulhu's appearance is described as looking like an octopus, a dragon, and a caricature of human form. Its name was given to the Lovecraft-inspired universe where it and its fellow entities existed, the Cthulhu Mythos.

Dave Barry

David McAlister Barry (born July 3, 1947) is an American author and columnist who wrote a nationally syndicated humor column for the Miami Herald from 1983 to 2005. He has also written numerous books of humor and parody, as well as comic novels. Barry's honors include the Pulitzer Prize for Commentary (1988) and the Walter Cronkite Award for Excellence in Journalism (2005).

Barry has defined a sense of humor as "a measurement of the extent to which we realize that we are trapped in a world almost totally devoid of reason. Laughter is how we express the anxiety we feel at this knowledge."

Dracula/The Rose

"Dracula"/"The Rose" is a 7" single (Megadisc MD 5270) by Dutch rock and roll band Claw Boys Claw. "Dracula" had earlier been released on the Hitkillers album, a collection of covers of Dutch hits from the 1960s and 1970s. The B-side, "The Rose," was recorded in 1988 but never released. On 25 March 1989, "Dracula" reached #85 on the Dutch charts, where it spent a total of 4 weeks.The two songs were also issued as a CD single (Megadisc MDC 5270) with a number of bonus tracks. These nine songs, most of which covers, were recorded on October 6, 1986 (on sleeve incorrectly listed as June 10, 1986), when the Claw Boys Claw, operating under the name "The Hipcats," opened for Nick Cave & The Bad Seeds in Vredenburg, Utrecht.

Ectrodactyly

Ectrodactyly, split hand, cleft hand, derived from the Greek ektroma (abortion) and daktylos (finger) involves the deficiency or absence of one or more central digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly (ectrodactyls) are often described as "claw-like" and may include only the thumb and one finger (usually either the little finger, ring finger, or a syndactyly of the two) with similar abnormalities of the feet.It is a rare form of a congenital disorder in which the development of the hand is disturbed. It is a type I failure of formation – longitudinal arrest. The central ray of the hand is affected and usually appears without proximal deficiencies of nerves, vessels, tendons, muscles and bones in contrast to the radial and ulnar deficiencies. The cleft hand appears as a V-shaped cleft situated in the centre of the hand. The digits at the borders of the cleft might be syndactilyzed, and one or more digits can be absent. In most types, the thumb, ring finger and little finger are the less affected parts of the hand. The incidence of cleft hand varies from 1 in 90,000 to 1 in 10,000 births depending on the used classification. Cleft hand can appear unilateral or bilateral, and can appear isolated or associated with a syndrome.

Split hand/foot malformation (SHFM) is characterized by underdeveloped or absent central digital rays, clefts of hands and feet, and variable syndactyly of the remaining digits. SHFM is a heterogeneous condition caused by abnormalities at one of multiple loci, including SHFM1 (SHFM1 at 7q21-q22), SHFM2 (Xq26), SHFM3 (FBXW4/DACTYLIN at 10q24), SHFM4 (TP63 at 3q27), and SHFM5 (DLX1 and DLX 2 at 2q31). SHFM3 is unique in that it is caused by submicroscopic tandem chromosome duplications of FBXW4/DACTYLIN. SHFM3 is considered 'isolated' ectrodactyly and does not show a mutation of the tp63 gene.

Fritz Von Erich

Jack Barton Adkisson Sr. (August 16, 1929 – September 10, 1997), better known by his ring name Fritz Von Erich, was an American professional wrestler, carnival attraction, wrestling promoter, and the patriarch of the Von Erich family. He was also the owner of the World Class Championship Wrestling territory.

Hammer toe

A hammer toe or contracted toe is a deformity of the muscles and ligaments of the proximal interphalangeal joint of the second, third, or fourth toe causing it to be permanently bent, resembling a hammer.Mallet toe is a similar condition affecting the distal interphalangeal joint.Claw toe is another similar condition, with dorsiflexion of the proximal phalanx on the lesser metatarsophalangeal joint, combined with flexion of both the proximal and distal interphalangeal joints. Claw toe can affect the second, third, fourth, or fifth toes.

Operation Eagle Claw

Operation Eagle Claw, known as Operation Tabas (Persian: عملیات طبس‎) in Iran, was a United States Armed Forces operation ordered by U.S. President Jimmy Carter to attempt to end the Iran hostage crisis by rescuing 52 embassy staff held captive at the Embassy of the United States, Tehran on 24 April 1980. Its failure, and the humiliating public debacle that ensued, damaged U.S. prestige worldwide. Carter blamed his loss in the 1980 U.S. presidential election mainly on his failure to secure the release of the hostages.The operation, one of Delta Force's first, encountered many obstacles and was eventually aborted. Eight helicopters were sent to the first staging area, Desert One, but only five arrived in operational condition. One encountered hydraulic problems, another was caught in a sand storm, and another showed signs of a cracked rotor blade.

During the operation's planning it was decided that the mission would be aborted if fewer than six helicopters remained operational, despite only four being absolutely necessary. In a move that is still discussed in military circles, the field commanders advised President Carter to abort the mission, which he did.As the U.S. force prepared to withdraw, one of the helicopters crashed into a transport aircraft which contained both servicemen and jet fuel. The resulting fire destroyed both aircraft and killed eight servicemen.In the context of the Iranian Revolution, Iran's new leader, Ayatollah Ruhollah Khomeini, used the failed operation as a propaganda tool. He claimed that the mission had been stopped by an act of God ("angels of Allah") who foiled the U.S. mission in order to protect Iran and his new conservative theocratic regime.

Professional wrestling holds

Professional wrestling holds include a number of set moves and pins used by performers to immobilize their opponents or lead to a submission. This article covers the various pins, stretches and transition holds used in the ring. Some wrestlers use these holds as their finishing maneuvers, often nicknaming them to reflect their character or persona. Moves are listed under general categories whenever possible.

Radical 87

Radical 87 meaning "claw", "nail" or "talon" is 1 of 34 Kangxi radicals (214 radicals total) composed of 4 strokes.

In the Kangxi Dictionary there are 36 characters (out of 49,030) to be found under this radical.

Space Marines (Warhammer 40,000)

In the fictional universe of Warhammer 40,000, the Adeptus Astartes (colloquial: Space Marines) are genetically modified superhuman warrior-monks, the elite warriors of the Imperium of Man. Space Marines have been one of the starter armies in almost every box edition of Warhammer 40,000, Space Hulk, and Epic. They also feature heavily in other Games Workshop products, such as books, films, and video games, and are central to the universe's setting.

Tailcoat

A tailcoat is a knee-length coat with the front of the skirt cut away, so as to leave only the rear section of the skirt, known as the tails.

The tailcoat shares its historical origins in clothes cut for convenient horse riding in the Early Modern era. Ever since 18th century, however, tailcoats evolved into general forms of day and evening formal wear, in parallell to how the lounge suit succeeded the frock coat (19th century) and the justacorps (18th century).

Thus, in 21st century Western dress codes for men, mainly two types of tailcoats has survived:

Dress coat, an evening wear with a squarely cut away front, worn for formal white tie

Morning coat (or cutaway in American English), a day wear with a gradually tapered front cut away, worn for formal morning dressIn colloquial language without further specification, "tailcoat" typically designates the former, that is the evening (1) dress coat for white tie.

The Giant Claw

The Giant Claw (a.k.a. The Mark of the Claw) is a 1957 American black-and-white science fiction giant monster film from Columbia Pictures, produced by Sam Katzman, directed by Fred F. Sears, that stars Jeff Morrow and Mara Corday. Both Sears and Katzman were well known as low-budget B film genre filmmakers. The film was released as a double feature with The Night the World Exploded.

Yellow Claw (DJs)

Yellow Claw is a Dutch DJ and record production duo from Amsterdam consisting of Jim Aasgier (born Jim Taihuttu) and Nizzle (born Nils Rondhuis). The duo's music is a mix of a wide range of genres and often incorporates elements from trap, hip hop, dubstep, big room house, hardstyle and moombahton.

Yellow Claw (comics)

The Yellow Claw is a fictional supervillain appearing in American comic books published by Marvel Comics. Created by writer Al Feldstein and artist Joe Maneely, the character first appeared in Yellow Claw #1 (cover-dated Oct. 1956), published by Atlas Comics, the 1950s predecessor of Marvel.

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