Grooming claw: Difference between revisions

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{{short description|Claw or nail on the foot of certain primates, used for personal grooming}}
[[Image:Varecia variegata foot with toilet-claw.jpg|thumb|Close-up of a [[ruffed lemur]]'s foot, showing the toilet-claw on the second toe and nails on all other toes]]
A '''toilet-claw''' ('''toilet claw''', '''grooming claw''') is the specialized [[claw]] or [[Nail (anatomy)|nail]] on the [[foot]] of certain [[primate]]s, used for [[personal grooming]]. All [[prosimian]]s have a toilet claw, but the digit that is specialized in this manner varies.<ref name=evolution>{{cite journal |author=Soligo, C., Müller, A.E. |year=1999 |title=Nails and claws in primate evolution |journal=Journal of Human Evolution |volume=36 |pages=97–114 |doi=10.1006/jhev.1998.0263 |pmid=9924135 |issue=1}}</ref> [[Tarsier]]s have a toilet claw on [[toe]] two and toe three. With one possible exception, in the suborder [[Strepsirrhini]], which includes [[lemur]]s, [[galago]]s and [[Lorisidae|lorises]], the toilet claw is on the second toe. The possible exception is the [[aye-aye]], which has claws instead of nails on toes 2 through 5. There is some debate concerning whether any of these claws (and if so which ones) are toilet claws.{{Fact|date=September 2008}}
 
A '''grooming claw''' (or '''toilet claw''') is the specialized [[claw]] or [[Nail (anatomy)|nail]] on the foot of certain [[primate]]s, used for [[personal grooming]]. All [[prosimian]]s have a grooming claw, but the digit that is specialized in this manner varies.<ref name=evolution>{{Cite journal | last1 = Soligo | first1 = C. | last2 = Müller | first2 = A. E. | doi = 10.1006/jhev.1998.0263 | title = Nails and claws in primate evolution | journal = Journal of Human Evolution | volume = 36 | issue = 1 | pages = 97–114 | year = 1999 | pmid = 9924135}}</ref> [[Tarsier]]s have a grooming claw on second and third [[toe]]s. In the suborder [[Strepsirrhini]], which includes [[lemur]]s, [[galago]]s and [[Lorisidae|lorises]], the grooming claw is on the second toe.<ref name="Schwitzer_etal2013">{{cite book | first1 = C | last1 = Schwitzer | first2 = R. A. | last2 = Mittermeier | first3 = E. E. | last3 = Louis Jr. | first4 = M. C. | last4 = Richardson | chapter = Family Daubentoniidae: Aye-aye | editor1-last = Mittermeier | editor1-first = Russell A. | editor1-link = Russell A. Mittermeier | editor2-first = Anthony B. | editor2-last = Rylands | editor3-first = Don E. | editor3-last = Wilson | editor3-link = Don E. Wilson | title = Handbook of the Mammals of the World. Volume 3. Primates | publisher = Lynx Edicions | location = Barcelona | year = 2013 | pages = 176–181 | isbn = 978-84-96553-89-7}}</ref> Less commonly known, a grooming claw is also found on the second pedal digit of [[night monkey]]s (''Aotus''), [[titi]]s (''Callicebus''), and possibly other [[New World monkey]]s.<ref name=Maiolino>{{Cite journal | last1 = Maiolino | first1 = S. | last2 = Boyer | first2 = D. M. | last3 = Rosenberger | first3 = A. | doi = 10.1002/ar.21498 | title = Morphological Correlates of the Grooming Claw in Distal Phalanges of Platyrrhines and Other Primates: A Preliminary Study | journal = The Anatomical Record | volume = 294 | issue = 12 | pages = 1975–90 | year = 2011 | pmid = 22042603| doi-access = free }}</ref>
The first toe is the large one, the equivalent of a human [[Hallux|big toe]]. However, in all these prosimians the foot is more or less hand-like. The first toe is opposable, like a human [[thumb]], and the second and third toes correspond approximately to the index and middle fingers.
 
The first toe is the large one, the equivalent of a human [[Hallux|big toe]]. However, in all these prosimians the foot is more or less hand-like. The first toe is opposable, like a human [[thumb]], and the second and third toes correspond approximately to the index and middle fingers.
Like a [[claw]] or a [[Nail (anatomy)|nail]], the toilet-claw is also made of [[keratin]]. It resembles a claw in both its lateral compression and longitudinal curvature. However, the tip is not as pointed, and it always stands at a steeper angle, a characteristic that also distinguishes it from a nail.<ref name=evolution/>
 
Like a [[claw]] or a [[Nail (anatomy)|nail]], the toilet-grooming claw is also made of [[keratin]]. It resembles a claw in both its lateral compression and longitudinal curvature. However, the tip is not as pointed, and it always stands at a steeper angle, a characteristic that also distinguishes it from a nail.<ref name=evolution/>
==Etymology==
 
The term for this prosimian anatomical structure comes from its function, which is to assist in grooming or toilet functions. The term ''[[wikt:toilet|toilet]]'', as used in American English, has changed over the past century. Historically, it was used to refer to personal grooming, not a lavatory device. Due to changes in the perception of the term, some sources have started to use the term ''grooming claw'' instead. However, the scientific literature still strongly favors the original term.
 
==Function==
 
The toilet-grooming claw is used in personal grooming to rake through the fur or scratch, particularly wherearound anthe individual cannot reach with its penishead and [[toothcomb]]neck.<ref name=Maiolino/>
 
==References==
{{reflist}}
 
== External links ==
* {{commonscatcommons category-inline|Toilet claws}}
 
[[Category:Primate anatomy]]
[[Category:Nails (anatomy)]]
 
{{primate-stub}}
 
[[et:Tualettküünis]]
[[fr:Griffe de toilette]]