Scratch (animal anatomy)
See also: Claw
The claw is an element that one touve at the end of the Patte S of the animals, often in the shape of hook. They are Phanère S.
At the Tétrapode S
In the mammals
They are elements at the end of the fingers of the legs being used for scraping, seizing or defending themselves. They are variable length according to the species, and formed of Alpha-keratin. At the Man, their equivalents are the Ongle S. According to the species, the claws are retractile (for example at the Felidae) or not (Ours).In certain countries, one practices the Onyxectomie (Greek onyx , the nail), or dégriffage , on the pet (Chat in particular). It is about an surgical operation which consists of the ablation of the claws.
In the birds
The birds generally carry claws only to the legs. The claws of the birds of prey are called the greenhouses.The fossil species of birds as the Archeopterix also carried from there to the wings. One knows only one current species of bird which still has claws on the wings: the Hoazin, whose chick has two claws which enable him to be clutched with the branches.
In the reptiles
The current reptiles have claws.The dinosaurs are known to have to have sharp-edged claws, such those which one could retouver on the remainders of Vélociraptor .
At the athropodes
The claws are expansions of Chitine on the final segments (tarsi) of the legs. They are not equivalent from a point of view philogenic to the claws of the tétrapodes.
See too
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