Ever wondered what dewclaws are for and where they came from? Believe it or not, once upon a time they served a serious purpose that helped dogs climb trees and live in trees, too. That weird nail on the side of your dog’s two front legs is what is thought to be the thumbs of the dog world.
Some dogs have only two declaws on their front legs, while other dog breeds have dewclaws on all four legs. Some even have double dewclaws on their hind legs. Dewclaws on the front legs are usually attached to the bone, while hind-leg dewclaws can wiggle around since they are not connected to the bone.
Dewclaws are… kind of weird. And although odd, dewclaws tell a very interesting story of where dogs originated from and who they used to be in the animal world.
What is the purpose of the dewclaw?
Dewclaws act as support to the carpal joint, aka the wrist of the dog. Dogs that run quickly (consider the Greyhound breed and all of its variants, for example) lean when they run to the side. The dewclaw offers stability.
We’ll talk about evolutionary purposes down further in the blog, but the dewclaw is a trait of the earlier version of dogs, called Miacis. Miacis lived in trees and climbed trees. Modern dogs still use the dewclaw for this purpose, too. Climbing dogs (think about the Belgian Malamute) use this claw to help them get traction.
Dogs also use the dewclaw for pulling themselves out of water. Dogs that swim water or have broken through ice will use their dewclaws to get out. You might have seen your dog use theirs when he or she is clawing their way out of the tub to avoid a bath.
Where Did Dewclaws Come From?
This is where the story of the dewclaw gets interesting.
Dogs are actually descendants of the Miacis— an animal that existed 40 million years ago. This animal climbed tall trees and often lived in the limbs. As this animal slowly evolved over time, the Miacis became a ground dweller. And as the Miacis began to live on the ground instead of in the trees, it became a specialized hunter, much like our canine friends today.
As time went on, though, the Miacis evolved into another species altogether, but both dogs and cats are thought to have come from this animal.
When the Miacis was in its heyday, the dewclaw was actually a part of its paw and served as a 5th nail. This 5th nail was kind of like a human’s fifth finger. This fifth claw helped the Miacis climb, grab hold of its prey, and keep its balance.
As the Miacis evolved to live on the ground instead of trees, they needed to be faster. Getting faster meant being able to eat. Their diet changed from things that fly to things that run, like rodents and other types of animals.
In order for the Miacis to become a quick predator, the 5th nail slowly crept up the leg over time. This acquisition happened so that the animal could have more support on the carpal joint while running, as stated previously.
Should Dewclaws Be Removed?
There is a debate about the dewclaw: should it be removed or left alone? Many canine professionals and organizations are split on this school of thought. Some, like the AKC, think that the dewclaw should be removed when dogs are puppies.
Since the dewclaw serves little purpose in modern dogs, many find the extra nail to be a health hazard. It is not uncommon for dogs to snag their dewclaws on things. Dogs can get the pesky nails stuck on just about anything, like blankets or fences.
Since most dewclaws are attached to the skin and not the bone (some breeds do have hind dewclaws attached to the bone), the skin can rip when the dewclaw is snagged. This can be excruciating for a dog. The AKC says to bypass that situation altogether with removal.
Other organizations think it’s cruel to remove a dewclaw since many dogs have no issue with it whatsoever. Removing a dewclaw, even with pain medication, can be very painful as well.
It’s a toss-up in the dog community on what to do with the dewclaw, but one this is for sure:
Dewclaws are like ancient artifacts that tell of a time long ago.