10 Fascinating Facts About Dog Dewclaws
Dog dewclaws, we often take them for granted, even removing them in puppies before considering whether dogs can put them to good use, but do dog dewclaws have a function?
What's the purpose of dog dewclaws? And most of all, do dogs really need them?
Let's discover several fascinating facts about dog dewclaws.
D is for dewclaw
1. Similar to Human Thumbs
Dewclaws are digits founds on the inside of the dog's leg. They may be found on the dog's front legs, but occasionally on the hind legs of certain dog breeds as well.
Dewclaws have three bones, two joints, and a nail that grows like a toenail. They also contain nerves and blood vessels.
They are essentially a fifth toe that is present on the dog's foot and is quite similar to a human's thumb, however, they don't share the same functionality as human thumbs.
Human thumbs are opposable which means that they can move in opposition to the other fingers of the hand. It is thanks to the ability of human thumbs to make contact with the other fingers that we are able to grasp and manipulate objects with great precision, a trait that sets us apart from many other species.
A dog's lack of opposable thumbs is one of the main reasons why dogs depend so much on their mouths to explore and interact with their surroundings.
2. Ancient Aids For Climbing Up
Did you know? Dewclaws are a remnant of a time in a dog's ancient past—as in over 40 million years ago—when a dog’s ancestors used to climb trees.
As these early dogs evolved into ground-dwelling animals, the presence of dewclaws turned redundant causing them to recede and be classified as vestigial.
Vestigial refers to structures or organs that have lost their original function and have become less important or even unnecessary.
3. Effective Torque Prevention
According to veterinarian and rehabilitation specialist Dr. Christine Zink, when dogs canter or gallop, and then make a quick turn, their dewclaws get in contact with the ground, digging in to provide more traction and preventing the dogs' legs from getting potentially twisted or injured.
4. Some Dogs Have Double
Some breeds have double rear dewclaws. Dogs with this feature are known as being "double-dewclawed."
According to the American Kennel Club, the Great Pyrenees is expected to have a single dewclaw on the foreleg and double dewclaws on each rear leg. The absence of double dewclaws on each rear leg is considered a fault in this breed.
In the Briard dog breed, the dewclaws on the front legs may or may not be removed. In the rear legs, two dewclaws must be present and ideally these rear dewclaws form additional functioning toes. The absence of double dewclaws on each rear leg is means for disqualification.
5. Getting a Grip
Although dogs lack our dexterous hand structure, dog declaws are useful for holding objects or treats while the dog is chewing.
6. Handy Ice Picks
Dewclaws may also come handy in the presence of ice. Should a dog be swimming or accidentally falls into a frozen pond, the dewclaws may function as effective ice picks to help the dog pull himself out of the water, explain Dr. Christine Zink and Janet B. Van Dyke in the book: "Canine Sports Medicine and Rehabilitation."
7. A Potential Cause of Problems
When routinely trimmed, dewclaws are prevented from overgrowing, but problems start when owners forget and then notice problems only later on.
Left to their own devices, dewclaws may grow so long that they start curving and end up forming a loop where the end risks embedding into the paw.
When this happens, the dog may develop an infection. Dog owners may only notice this once they start smelling an unpleasant odor when nearby the dog or when their dogs start to repeatedly lick the area. When things progress to this level, veterinary care is often paramount as there may be an infection.
Dewclaws have also been reported to get caught on carpets and to cause corneal scratches to a dog's eyes when dogs may paw at them.
8. Dewclaws May Be Removed Early
Because of the above risks and/or for the purpose of adhering to certain breed standards, breeders will remove dewclaws from a dog's front legs when the dog is puppy younger than 5-days-old. The breeder simply snips them off using a nail clipper without anesthetic.
9. Not as Problematic as Thought
According to a study, dewclaws were found to be at low risk for injury in agility dogs, consistent with previous observations in racing Greyhounds where dewclaws were reported as being weight-bearing appendages.
As such, the authors of the study advise against elective surgical removal of forelimb dewclaws for dogs training and competing in agility activities.
10. Involved in Legends
Did you know? In the past, in the Southern United States, there was belief that dogs who sported dewclaws in their rear legs were immune to the venom from a snake bite. People were so convinced that they would show you the dog's rear dewclaws and claim that these little suckers were able to “suck up all the poison.”
References:
- Why Puppies Do That: A Collection of Curious Puppy Behaviors by Tom Davis
- Do the Dew(claws)? by M. Christine Zink DVM, PhD, DACVSMR
- Canine Sports Medicine and Rehabilitation by Chris Zink, Janet B. Van Dyke · 2018
- Sellon, D., Martucci, K., Wenz, J., Marcellin-Little, D., Powers, M., & Cullen, K. (2018). A survey of risk factors for digit injuries among dogs training and competing in agility events. Journal of the American Veterinary Medical Association
- Prole JHB. A survey of racing injuries in the Greyhound. J Small Anim Pract 1976
Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice or behavioral advice. If your dog is acting sick or aggressive please consult with a qualified professional for proper diagnosis and treatment.
