You know that weird, dangly toenail that some dogs have partway up their forelimb? Have you ever wondered what possible purpose that thing could serve? In some dogs the digit is firmly attached by muscle and tendon. In others, there is nothing but a thin layer of skin keeping it in place. So how could a strange little toenail that doesn't even touch the ground ever be of any use to your dog?
The answer varies depending on the dog. Some feel that dew claws should be removed from puppies within days of birth, and this has come to be expected in many breeds. For others, dew claws are considered part of the breed's unique standard. Not only is removal uncommon in breeds like the Great Pyrenees, it is highly frowned upon by the AKC
and serious breeders.
Dew claws were named for their positioning on the leg. They sit at just the right height to skim the morning dew when your dog walks through the grass. For the majority of dogs, that about sums up the action that the dew claw gets in a day. Unfortunately, the high position of the digit is what causes issues for some dogs.
Since the nail does not contact the ground, it may grow out more quickly than the other nails causing injury. Claws with poor attachments can get caught in carpeting, fabric or weeds and be torn.
Yet many dogs use this fifth digit for a variety of little tasks. For those dogs who have dew claws with muscular attachments, they can be helpful in gripping bones during chewing. This purpose is a definite throwback to our dogs' ancestors. The dew claw would have been quite useful for grasping and gripping carrion in order to tear away the meat with their teeth.
Certain breeds of dog have dew claws that are particularly strong and maneuverable. Basenjis, Catahoula Leopard Dogs, and New Guinea Singing Dogs can climb trees nearly as well as cats, thanks in part to their genetically powerful and functional dew claws. This adaptation likely came about in these breeds out of necessity. With food in scarce supply, the ability to climb after prey was a major benefit. The trait makes these breeds favorites among hunters in certain areas.
The Great Pyrenees, St. Bernard and Briard are genetically predisposed to rear dew claws, and even double
rear dew claws. As far as the purpose of rear dew claws, researchers believe that they may help provide stability when walking on rough terrain. The breeds above are known to be powerful working dogs in snowy and mountainous areas so additional balance is a definite advantage.
Veterinarian Dr. M. Christine Zink
of Johns Hopkins University works exclusively with canine athletes. She believes that dew claws may be far more important to our dogs than previously thought. She has noticed a trend of carpal (wrist) arthritis in agility and hunting dogs that have had their dew claws removed.
Using stop-action photography, Dr. Zink has been able to show that when dogs run at full speed, their entire foot contacts the ground, including the dew claw. She believes the claw stabilizes the rest of the leg by digging into the ground, preventing twisting or torque. Dr. Zink also feels that removing dew claws from working or agility dogs could cause related muscle groups in the leg to atrophy leading to injury.
Whether your dog is dew claw-free or polydactyl (having more than the standard number of digits), the toenails should always be properly maintained. Often dew claws can be overlooked during routine trims leading to ingrown nails and infections. If you think that your dog's dewclaws could be causing more problems than good, discuss the possibility of removal and other options with your veterinarian.
H/T to canidae.com
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