Understanding Dew Claws on Dogs
If you've ever noticed an extra nail sitting higher up on your dog's leg, that's the dewclaw. Most dogs have four nails on each rear foot and five on their front feet. That fifth nail, located on the upper, inner part of the front leg, is what we call the dewclaw. It's essentially the canine equivalent of a human thumb or big toe.
Anatomy and Placement
Looking closely at a dog's front foot, you'll see that the toes touching the ground correspond to our pinky, ring finger, middle finger, and index finger. The dewclaw sits off to the side—like our thumb. On some dogs, you'll also find dewclaws on their hind legs (the 'big toe' equivalent), though these are less common and often only attached by skin rather than bone.
- Front dewclaws: Usually present in all dogs; typically attached by bones and ligaments.
- Rear dewclaws: Less common; often attached only by skin and more mobile.
- Double dewclaws: Some breeds (like Great Pyrenees or Briards) may have two dewclaws per rear leg as part of breed standards.
Functionality of Dew Claws
Dewclaws aren't just decorative. Those attached by bone—especially on the front legs—have definite purposes:
- Traction and Stability: When dogs run at high speeds or navigate slippery surfaces, their front dewclaws can touch the ground, providing extra grip and helping stabilize their wrist joints.
- Gripping Objects: Some dogs use their dewclaws to hold bones or toys while chewing.
- Climbing Assistance: Dewclaws can help certain breeds climb out of water or over obstacles.
The usefulness of rear or double dewclaws is less clear since they're usually not connected by bone and rarely touch the ground. In some breeds, however, they're considered a hallmark trait.
Dew Claw Genetics
The presence of additional rear dewclaws is often due to genetic factors (notably involving the LMBR1 gene). This condition—called hind-limb-specific preaxial polydactyly—results in extra toes that are usually only attached by skin. While most wild canids have four claws per rear foot, domestic breeds sometimes display these extras due to selective breeding.
Dew Claw Removal: Pros and Cons
The decision to remove a dog's dewclaw is sometimes made for cosmetic reasons (to meet show standards) or out of concern for injury. However, evidence suggests that injuries to firmly attached front dewclaws are uncommon. In fact, removing them may increase risk for arthritis or foot injuries because they play a role in stabilizing joints during movement.
- Dewclaw removal should be done only if there's repeated injury or persistent medical issues.
- If removal is necessary (for example, with loosely attached double rear dewclaws), it's best performed by a veterinarian when puppies are under five days old using local anesthesia.
- Certain breeds require intact dewclaws for show eligibility—removal would disqualify them from competition.
Dew Claw Injuries and Maintenance
Dew claws can suffer from injuries such as being pulled off, broken, split, infected, or growing inward. These injuries are painful and prone to infection. If you notice any damage or swelling around your dog's dew claw, consult your veterinarian promptly; treatment may involve trimming under sedation or even removal if severely damaged.
Caring for your dog's dew claws is much like caring for their other nails—but with an added challenge: since they don't always touch the ground during walking or running (especially rear ones), they don't wear down naturally. Overgrown dew claws can curl into the skin or snag on objects. Here's how to keep them healthy:
- Trim regularly: Check if you can slip your finger under the nail without catching—if not, it's time for a trim.
- Inspect for overgrowth or injury: Look for redness, swelling, discharge, or signs of pain.
- If injured: Seek veterinary care; antibiotics or pain relief may be needed after treatment.
Bones and Toes: Canine Anatomy Recap
A typical dog has 18 toes: four weight-bearing toes per paw plus two front dewclaws. The front dewclaw contains bones and joints just like other digits but doesn't have as much range of motion as our thumbs do. Rear dewclaws (when present) often lack bones entirely—they're mostly skin attachments prone to overgrowth.
Dew Claws Beyond Dogs
Dewclaws aren't unique to dogs—you'll find similar structures in cats (where they're functional for hunting), cattle, deer, birds, and reptiles. In these animals too, they're usually positioned higher up on the limb than regular toes and may serve unique purposes depending on species.
Caring for Dew Claws: Best Practices
- Trim regularly: Especially important for indoor pets or those with minimal outdoor activity.
- Monitor health: Watch for signs of infection or ingrown nails—these issues require prompt attention.
- Avoid unnecessary removal: Unless there's persistent injury or disease risk (particularly with loosely attached rear ones), keep functional front dewclaws intact for joint health benefits.
Dew claws are more than just vestigial remnants—they serve important roles in stability and traction for many dogs. With regular maintenance and thoughtful consideration regarding removal decisions, you can help ensure your dog's paws stay healthy throughout their life.
