dewclaw is a digit-vestigial in some animals - at the feet of many mammals, birds, and reptiles (including some extinct commands, such as certain theropods). Usually grows tall in the legs as happens in digital species, when the animal stands, it does not make contact with the ground. In dogs, a dewclaw is on the inside of the foot, positioned similarly to the human thumb.
Video Dewclaw
Dog
Dogs almost always have dewclaws on the inside of the front legs and sometimes also on the hind legs. Unlike the front dewclaw, the rear dewclaw tends to have little bone or muscle structure in most breeds. It is normal, although not biologically necessary, that certain breeds will have more than one dewclaw on the same claws. At least one of these dewclaws is not well connected to the foot, and in this case it is often removed surgically. When the dog has additional dewclaws other than the usual on each front foot, the dog is called a double dewclawed. There is some debate about whether dewclaw helps dogs to get traction when they run because in some dogs, dewclaw makes contact as they walk and nails in dewclaw often run out in the same way as the nails on their other toes do, from contact with the ground. In many dogs dewclaws never touch the ground. In this case, the nail dewclaw never fades, and is often pruned to keep it on a safe length.
The dewclaws are not a dead complement. They can be used to hold the bones lightly and other items the dog holds with the claws. In some dogs, these claws may not appear connected to the foot at all except by the folds of the skin; in such dogs, claws can not be used for gripping because the claws can be easily folded or rotated.
Lambclaws back
Kanida has four claws on the hind legs, though some domestic or individual dog breeds have extra or more rare claws, two, as is the case with beauceron. The more technical term for this additional digit on the hind leg is the pre-pax pre-frontal specific . Some genetic mechanisms may cause rear dewclaws; they involve the LMBR1 gene and related parts of the genome. The rear dewclaw often has no phalanx bone and is only attached to the skin.
Dewclaw removal
There is some debate as to whether dewclaws should be removed surgically. The argument to eliminate states that dewclaws are weak numbers, barely attached to the legs, and thus they can tear in half way or easily catch something and break, which can be painful and prone to infection. Dewclaw removal is most easily done when the dog is young, about 2-5 days. This can also be done on older dogs if necessary although surgery may be more difficult. This operation is quite easy and can be done with local anesthesia if the finger is not connected properly to the foot. Many dogs can not resist licking the surgical site in the weeks after the procedure, so an Elizabethan or bitter collar can be used to limit this behavior, thereby preventing infection.
Some puppies are generally sold by dew clawed breeders, ie with dewclaws removed (as by veterinarians) for health and safety reasons perceived. Some breed standards also need them.
Dewclaws and locomotion
Based on stop-action photographs, vet M. Christine Zink of Johns Hopkins University believes that all of the forelegs, including dewclaws, contact the ground while running. During walking, dewclaw digging to the ground prevents twisting or torsion on the rest of the foot. Some tendons connect the front dewclaw to the muscles in the lower leg, further demonstrating the front dewclier function. There are indications that dogs without dewclaws have more leg injuries and are more prone to arthritis. Zink recommends "for working dogs is best for dewclaws not to be amputated." If dewclaw suffers a traumatic injury, problems can be addressed at the time, including amputations if necessary. "
Maps Dewclaw
Cat
Family members of cats - including domestic cats and stray cats like lions - have dewclaws. Generally dewclaw grows on the inside of each forefoot but not on both hind legs.
The dewclaw on some cats is not vestigial. Felids are wildly using dewclaw in hunting, where it provides additional claws to catch and hold prey.
Shellfish
The hoofed animals walk on the toes of the special toes, the toenails. The hoofed-toed animals run on a pair of hooves, but many also have a pair of dewclaws outside on each leg. This is a foot that is a bit distant than the main toenail, and has a structure similar to them. In some species (such as cattle) dewclaws are much smaller than nails and never touch the ground. In others (such as pigs and many deer), they are only slightly smaller than nails, and can reach the ground in soft conditions or when jumping. Some hoofed animals (such as giraffes and modern horses) do not have dewclaws. Video evidence shows some animals use dewclaw in grooming or scratching themselves or having a better understanding during mating.
References
External links
- Another view in Dewclaws
Source of the article : Wikipedia
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