Dewclaws are vestigial toenails located relatively high on the interior of a dog's leg. All dogs have dewclaws on their front legs, and some breeds have them on the hind legs as well. Some dogs have double dewclaws, which means they have two extra digits on each affected leg.
Although dewclaws are often believed to be functionless, that is a myth. Dogs can use their front dewclaws to help grip bones and toys as they chew. The dewclaws also can provide traction for dogs that are running or climbing. Some dewclaws are firmly attached to the leg and have more mobility, while others are very loosely attached. Veterinarians sometimes recommend the surgical removal of the latter because of the high chance of injury.