Dogs are a digitigrade species: they walk on their digits. Paws have four digits that make contact with the ground, but sometimes their is an inside digit higher up that doesn’t connect with the ground. That is a dewclaw. Most dogs have dewclaws on their front paws only, it’s rare to have a rare dewclaw. There are a few breeds where a rear dewclaw is a breed standard, such as the Great Pyrnees or Briard. What is/was the purpose of a dewclaw?
The Great Pyrenees was bred to be a guard livestock and the ground they walked on was rough and uneven. The dewclaw on the rear feet functioned to give the dogs greater stability. (This is much the same purpose of front dewclaws.) Since most dogs aren’t used for herding, hunting or guarding anymore, essentially the dewclaw (rear or front) is now a non functional extra “appendage,” that is expendable, which they often are.
Many breeders will often have dewclaws removed between 3 to 5 days of age. At this age, the dewclaw is so loose, it’s easy for a veterinarian to remove.
If your dog’s breeder didn’t remove the dewclaw, you can make the decision. Consider where your dog will be spending much of his time and how much the dewclaw is “in the way.” Any dewclaw that is loose regardless of your dog’s lifestyle, should be removed by your veterinarian immediately. A loose dewclaw can get caught on anything and will cause your dog tremendous pain.
The easiest (and most preferred time by veterinarians) time to remove dewclaws are during your dog’s spay/neuter procedure as your dog will be under general anesthesia anyway. This anesthesia doesn’t carry the same risks as other types and the older a dog is, the more risks are associated with using any kind of anesthesia.
If you choose to keep your dog’s dewclaw (especially in the front) because it’s held so close to your dog’s skin, you will need to pay as much attention to it as you do to his normal claws. Since dewclaws don’t make contact with the ground, they don’t have a chance to get worn down like regular claws. These dewclaws will grow in a “curlier” fashion and can grow into your dog’s skin and, if not trimmed, can cause your dog pain. Once a dewclaw curls in that much, trimming it is extremely difficult; so trim dewclaws often.
If you have any questions about your dog’s dewclaws, consult your vet. Between the two of you, you’ll be able to make a completely informed decision about what’s the best course of action to take for both you and your dog.