If your dog is chomping non-stop at his bottom, it can be enough to drive both of you up the wall. Although the constant biting is often linked to common ailments such as swollen anal glands or fleas, seek a veterinarian’s advice to rule out the possibility of other causes.
Full Anal Glands
Normally anal glands drain themselves as a dog defecates. When the anal glands do not properly drain, fluid builds up and causes pressure and discomfort. Your dog might show her discomfort by biting at her behind or by “scooting” across the floor. A dog is scooting if she assumes a sitting position and then uses her front legs to drag her bottom across the floor or the ground.
Relieve this problem by having the anal glands drained or expressed. Typically a dog groomer, veterinarian or a vet tech will apply pressure to the glands to drain out the fluid. It is possible for dog owners to do this as well, but don't attempt it on your own. Instead, ask a professional to show you how it’s done and then assess whether you would feel comfortable expressing the glands in the future.
Fleas can also cause dogs to bite at their behinds. Fleas often congregate under the base of a dog’s tail, an area that tends to be damp and warm. Skin irritation, missing fur and scabs caused by biting or scratching are also indicators that fleas are present, according to the ASPCA. Treat fleas as quickly as possible because they are challenging to eliminate once they get a foothold on your dog and in your home.
These parasites survive by literally feeding on the blood of an animal. In smaller dogs and puppies, severe or prolonged flea infestations can cause anemia from a loss of blood. You can usually spot fleas by separating your dog’s fur with your fingers and looking closely at the skin. If you see fleas on your dog, ask your veterinarian to prescribe an appropriate treatment plan.
Sometimes dogs become fixated on a certain behavior, and this can include biting at their bottoms. Obsessive-compulsive behaviors are sometimes related to anxiety or stress in a dog’s environment. In other cases, there is no apparent cause. If your dog’s bottom-biting is behavioral, a professional dog behaviorist can help stop it.
When a dog bites at his bottom, it does not necessarily indicate anything serious, but that doesn't mean you should ignore it. Addressing the issue promptly is the safest bet to ensure your dog remains healthy -- and comfortable.