A dew claw is an extra digit on a dog’s foot, positioned higher up on the leg than the other four toes. Think of it as roughly equivalent to a human thumb or big toe. Most dogs have dew claws on their front legs, and some also have them on their rear legs. While they might look like evolutionary leftovers, front dew claws actually serve a real purpose during movement.
Where Dew Claws Sit on the Leg
On the front legs, dew claws grow from what corresponds to the “thumb” position, a few inches above the paw on the inner side of the leg. Unlike the other four toes, they don’t make contact with the ground when a dog is standing still. Front dew claws are connected to the leg by bone, tendons, and muscle, giving them a solid attachment and some range of motion.
Rear dew claws are a different story. When present, they tend to be attached only by a flap of skin with little or no bone structure underneath. This loose attachment makes them more prone to snagging and tearing. Many dogs don’t have rear dew claws at all.
What Dew Claws Actually Do
Front dew claws aren’t just decorative. When dogs run, their front feet bend enough that the dew claws make contact with the ground. At high speeds, especially when turning, or on slippery surfaces, these digits provide extra traction and help stabilize the wrist joint. If you’ve ever watched a dog chew on a bone or toy, you’ve probably noticed them using their dew claws to grip and hold objects in place. Working dogs, herding breeds, and agility dogs rely on this grip more than most.
Rear dew claws, by contrast, rarely serve any biomechanical function. They don’t touch the ground during movement, and their loose attachment means they can’t provide meaningful stabilization.
Breeds With Double Dew Claws
Some breeds are known for having double dew claws on their hind legs, meaning two extra digits on each rear foot instead of one. The Great Pyrenees is the most recognizable example. In this breed, rear dew claws are so expected that breed standards require them.
The genetics behind this trait are more complex than a simple on-or-off switch. Research on the gene LMBR1, located on canine chromosome 16, has identified mutations in a regulatory region that influence whether extra digits form on the hind limbs. In Great Pyrenees specifically, dogs with two copies of one version of the gene tend to develop bilateral double dew claws, but the trait doesn’t follow a clean inheritance pattern. Genetic background and other modifying factors play a role, which is why the number and formation of rear dew claws can vary even within the same litter.
The Norwegian Lundehund takes things further. This rare breed can have extra toes on both the front and hind feet, an adaptation that historically helped them climb rocky cliffs to hunt puffins. The genetic basis for this more extensive polydactyly is still poorly understood compared to the hind-limb-only version.
Dew Claws Beyond Dogs
Dogs aren’t the only animals with dew claws. Cats have them on their front paws (the inner toe that sits higher than the rest). Livestock like cattle, pigs, sheep, and goats also have dew claws, the small accessory toes visible at the back of the hoof above the main two digits. In these cloven-hoofed animals, dew claws serve no functional purpose and simply sit above the ground as remnants of ancestral toe structure.
Common Injuries
Dew claw injuries are one of the more frequent minor emergencies vets see. The most common problems are tears, cracks, and overgrowth that causes the nail to curl into the skin. Rear dew claws that are loosely attached are especially vulnerable to catching on carpet, brush, fencing, or fabric and ripping partially or fully off.
A torn dew claw typically bleeds noticeably, and dogs will often limp or lick the area persistently. If the tear is partial, with the nail hanging but still attached, a vet will usually trim or remove the damaged portion under light sedation. Full tears that expose the underlying tissue may need cleaning, a short course of antibiotics over 7 to 10 days to prevent infection, and a light bandage. Pain is usually manageable and resolves within 2 to 3 days.
Trimming and Routine Care
Because dew claws don’t touch the ground during normal walking, they never wear down naturally the way the other nails do. This makes regular trimming essential. Without it, the nail will eventually curve in a full circle and grow into the pad, causing pain and infection. Many dog owners trim the main nails on schedule but forget the dew claws entirely.
A scissors-style nail clipper works best for dew claws. The digit can usually be bent gently away from the leg, giving you a clear view and easy access. Trim small amounts at a time to avoid cutting into the quick, the blood vessel inside the nail. If you’re trimming your dog’s nails at home, check the dew claws every 2 to 3 weeks, since they grow at the same rate as the other nails but get zero natural wear.
Should Dew Claws Be Removed?
Dew claw removal is an elective surgery in most cases. Some breeders have it done when puppies are just a few days old, before the tissue has fully developed, which makes it a simpler procedure. In adult dogs, it’s a more involved surgery requiring anesthesia and a recovery period.
The case for removal is strongest with loosely attached rear dew claws that snag repeatedly and cause ongoing injury. Front dew claws, because they’re firmly attached by bone and serve a functional role in traction and grip, are generally worth keeping. Removing a functional front dew claw eliminates the stabilization benefit and removes a digit the dog actively uses.
Veterinary opinion has shifted over the years. Routine removal for cosmetic reasons has become less common, with more vets recommending removal only when there’s a clear medical reason, such as repeated trauma or a dew claw so loosely attached it’s a constant risk. The decision often comes down to the individual dog’s anatomy: a tightly attached dew claw that stays close to the leg and gets trimmed regularly will rarely cause problems, while a floppy rear dew claw dangling by skin alone is an injury waiting to happen.