The dew claw is a functional digit on your dog’s leg that works like a rough equivalent of a thumb. On the front legs, it helps with grip, stability during turns, and holding objects. While it sits higher than the other toes and doesn’t touch the ground when your dog is standing still, it makes contact during movement and serves several practical purposes that many dog owners never notice.
How Dogs Use Their Front Dew Claws
Front dew claws engage every time your dog runs, turns, or handles an object. When a dog sprints and makes a sharp turn, the front dew claw digs into the ground to stabilize the lower leg and prevent torque on the wrist joint. Without that extra point of contact, all the rotational force transfers to the other four toes.
You can see dew claws at work in a much simpler context: watch your dog chew a bone or hold a toy between its front paws. The dew claws act as opposing grips, letting the dog pin an object in place and rotate it. Dogs also use them when digging and when pulling themselves up steep or uneven ground. It’s a small digit, but it’s surprisingly active.
The Anatomy Behind the Function
Front dew claws are not just flaps of skin with a nail attached. They connect to the leg through bone, and working tendons run through them. The deep digital flexor tendon attaches to the outermost bone of the digit, while extensor tendons attach on the opposite side. This means the dog can actively flex and extend the dew claw, not just drag it passively.
One anatomical quirk: the front dew claw has only two bones instead of the three found in the other toes. It’s missing the middle bone, which is part of why it’s shorter and sits higher on the leg. Rear dew claws, when present, are a different story. Many rear dew claws lack a solid bone connection and are attached mainly by skin, making them truly vestigial in most breeds.
Why Some Breeds Have Double Dew Claws
A handful of breeds carry double dew claws on their hind legs, meaning two claws per rear leg instead of one or none. The Great Pyrenees is the best-known example, but the Briard and Beauceron also carry this trait. Unlike the floppy rear dew claws found on other breeds, double dew claws in these dogs are supported by bone and muscle, making them genuinely functional.
The trait is believed to be an ancient adaptation for mountainous terrain. Great Pyrenees originated in the steep Pyrenees Mountains, where they guarded livestock and chased predators across rocky slopes. The extra digits provide additional traction and grip on uneven surfaces, acting almost like built-in crampons. They may also serve as a braking mechanism when racing downhill. Breed standards for these dogs actually require the double dew claws, and removing them would be a disqualification in the show ring.
Interestingly, wolves and other wild canids don’t typically have rear dew claws unless their ancestors interbred with domestic dogs. The double rear dew claw appears to be a trait that developed within specific domestic breeding lines rather than something inherited directly from wild ancestors.
Evidence That Dew Claws Prevent Injuries
One of the strongest arguments for keeping dew claws comes from a study published in the Journal of the American Veterinary Medical Association that surveyed digit injuries in agility dogs. Dogs without front dew claws were nearly twice as likely to injure their other toes compared to dogs that still had them (with an odds ratio of 1.9). The researchers concluded that the absence of front dew claws may itself be a risk factor for injuries to the remaining digits.
The same study found that dew claw injuries themselves were uncommon. Out of 110 dogs with front dew claws, only 8 experienced an injury to that digit, and 7 of those 8 injuries were described as minimal or mild. This lines up with observations in racing Greyhounds, where dew claw injuries are also rare. The data suggests that removing dew claws to “prevent injury” may actually create more injury risk than it eliminates.
The Removal Debate
For decades, many breeders and veterinarians routinely removed dew claws from puppies within the first few days of life, treating it as a preventive measure. The thinking was that a loose, dangling claw would inevitably snag on something and tear. That logic applies more reasonably to floppy rear dew claws with no bone attachment, but it was often applied to front dew claws too, where the anatomy and function are quite different.
The veterinary perspective has shifted. Given that front dew claws are structurally connected, actively used, and associated with lower injury rates in the remaining toes, routine removal is harder to justify. Rear dew claws that are loosely attached and prone to catching on things may still be reasonable candidates for removal in some cases, but even that decision is increasingly made on a case-by-case basis rather than as a blanket policy.
Keeping Dew Claws Healthy
Because dew claws don’t contact the ground during normal walking, they don’t wear down naturally the way other nails do. This makes them prone to overgrowth. A dew claw nail that grows too long will curve in a circle and eventually pierce the pad or skin of the leg, causing pain and infection. A UK veterinary study found that overgrown or ingrown nails and broken claws (including dew claws) were among the most common clinical reasons dogs needed nail care at the vet, accounting for about 21% of nail-related visits combined.
Check your dog’s dew claws every few weeks and trim them whenever they start to curve. If you’re trimming the other nails at home, it’s easy to forget the dew claw since it’s tucked higher on the leg. Dogs with thick fur around the dew claw area need extra attention because the nail can disappear into the coat and grow unnoticed for months.
Signs of a dew claw problem include limping, licking at the inner wrist area, swelling, or visible redness around the nail base. A torn dew claw nail will often bleed and cause obvious pain. If you notice thick or discolored discharge, swelling that spreads up the leg, or your dog refusing to bear weight on the paw, that points to infection and needs veterinary attention promptly.