<P> Canids have four claws on the rear feet, although some domestic dog breeds or individuals have an additional claw - or more rarely, two, as is the case with the beauceron . A more technical term for these additional digits on the rear legs is hind - limb - specific preaxial polydactyly . Several genetic mechanisms can cause rear dewclaws; they involve the LMBR1 gene and related parts of the genome . Rear dewclaws often have no phalanx bones and are attached by skin only . </P> <P> There is some debate as to whether dewclaws should be surgically removed . The argument for removal states that dewclaws are a weak digit, barely attached to the leg, and thus they can rip partway off or easily catch on something and break, which can be painful and prone to infection . Dewclaw removal is most easily performed when the dog is young, around 2--5 days of age . It can also be performed on older dogs if necessary though the surgery may be more difficult then . The surgery is fairly straightforward and may be done with local anesthetics if the digit is not well connected to the leg . Many dogs can't resist licking the surgery site in the weeks following the procedure, so an Elizabethan collar or bitterant may be used to curtail this behavior, thus preventing infection . </P> <P> Some pups are commonly sold by breeders "dew clawed," that is with the dewclaws removed (as by a veterinarian) for perceived health and safety reasons . A few breed standards also call for it . </P> <P> Based on stop - action photographs, veterinarian M. Christine Zink of Johns Hopkins University believes that the entire front foot, including the dewclaws, contacts the ground while running . During running, the dewclaw digs into the ground preventing twisting or torque on the rest of the leg . Several tendons connect the front dewclaw to muscles in the lower leg, further demonstrating the front dewclaws' functionality . There are indications that dogs without dewclaws have more foot injuries and are more prone to arthritis . Zink recommends "for working dogs it is best for the dewclaws not to be amputated . If the dewclaw does suffer a traumatic injury, the problem can be dealt with at that time, including amputation if needed ." </P>

Why does my dog have 2 dew claws