Who can figure dogs out? One minute they're snoozing on the couch, the next they're spinning in circles trying to catch their tails. Although it can certainly be amusing to watch as your canine friend becomes a whirling dervish, you may want to do a little sleuthing to find the reason behind his twirls.

It could be boredom or there could be a medical reason for your dog's unusual twists.

Possible reasons for tail chasing

beagle puppy with tail up in the air Puppies often chase their tails because they think tails are toys. (Photo: Sigma_S/Shutterstock)

There are many reasons why dogs might chase their tails, veterinary behaviorist Rachel Malamed, DVM, DACVB tells MNN. "We always try to explore medical reasons first but sometimes there are both medical and behavioral reasons that exist simultaneously."

Rear end medical problems — Itching and pain in the nether region can cause dogs to chase their tails, says Lynn Buzhardt, DVM, of VCA Hospitals. They might tail chase when they have internal parasites like tapeworms that have made their way out, she says.

"Tail-chasing also occurs when the dog itches around the rear end due to external parasites like fleas or food allergies. In addition, discomfort in the tail area due to impacted anal glands or neurological problems affecting the caudal spine often cause dogs to nip at their tails." That's why a trip to the vet is so important.

High cholesterol — In a small Turkish study, researchers found that dogs with higher cholesterol levels were more likely to chase their tails than pups with lower levels. Veterinarian Dr. Marty Becker says, "Dogs may chase their tails because the high cholesterol levels have blocked the flow of brain hormones controlling mood and behavior. The study suggests that an increase in exercise could help lower the tail-chasing."

Behavioral issues — Your dog may chase his tail due to anxiety-related issues such as compulsive disorders or displacement behavior, says Malamed. "A displacement behavior is a normal behavior that occurs outside of the normal context and may be related to a specific anxiety trigger." She says she had one canine patient that would chase his tail each time his owners hugged. Another chased her tail in response to a specific sound.

Tail chasing can also become a compulsive behavior, in that it has no specific trigger and can interfere with your dog's everyday activities. Some breeds are more prone to specific compulsive behaviors. According to WebMD, "German shepherd dogs seem vulnerable to tail-chasing compulsions. Sometimes they even bite and chew their tails when they 'catch' them, causing hair loss or serious injury."

woman playing frisbee with dog Give your dog lots of mental and physical stimulation to keep him happy. (Photo: oneinchpunch/Shutterstock)

Boredom — When some dogs don't get enough physical or mental stimulation, they find ways to amuse themselves or release their bottled energy. That may include spinning in circles, going after their tails.

"If a dog is bored, frustrated or has pent-up energy, this could manifest as tail-chasing behavior or other less desirable behaviors," says Malamed. "If a dog does not have enough enrichment, exercise or spends long periods of time at home alone or in confinement, this type of behavior can be a sign of stress. Treatment includes adding complexity to the environment, limiting or avoiding confinement, more interactions with people/dogs and other activities."

Attention-seeking behavior — Just like little kids act up (in good and bad ways) for adults who give them attention, some dogs learn that we laugh or call out when the tail chasing starts. "If a dog is rewarded with verbal praise or an exciting reaction from the audience, it may be motivated to perform the behavior again," says Malamed.

"The act of chasing the tail may be fun and self-reinforcing and the more a behavioral is practiced, regardless of the cause, the more it is reinforced. Once identified as an attention-seeking behavior, the most effective way to stop the behavior is to stop rewarding it with attention by consistently ignoring the behavior." Just be sure to give your dog lots of ways to earn affection and attention when he's not chasing his tail.

Puppy silliness — Puppies may chase their tails because they just discovered them. "Hey! Look at that silly thing! I think I'll play with it." Young dogs might think their tails are toys and it's a phase they typically outgrow as they age, writes Buzhardt.

What science says

A team of French, Canadian and Finnish researchers took a comprehensive look at the genetic, environmental and other personal history factors that might influence tail chasing in dogs. They studied 368 dogs from four breeds (bull terriers, miniature bull terriers, German shepherds and Staffordshire bull terriers), asking their owners about their personalities, habits and backgrounds.

They found that the tail chasers were often taken from their mothers at an earlier age, usually leaving their moms at seven instead of eight weeks. Dogs that received dietary supplements were less likely to chase their tails than those who didn't receive vitamins or minerals. The study found that tail chasers seemed to be lacking certain nutrients, particularly vitamin B6 and vitamin C.

Tail chasers tended to have other obsessive behaviors such as "trance-like freezing," licking, pacing, and snapping at invisible flies or lights. Neutered females were less likely to chase their tails, which suggested to the researchers that ovarian hormones play a part.

They also found that tail chasers were shyer and less aggressive towards people (they were less likely to bark, growl or bite). They also had more noise phobia, especially when it came to fireworks.

The study, aptly named "Environmental Effects of Compulsive Tail Chasing in Dogs," was published in the journal PLOS One.

What to do

First, make sure there's no medical reason or compulsive disorder behind your pet's tail chasing.

"If the behavior is relatively minor and the veterinarian rules out pain and/or OCD, pet parents should interrupt any tail chasing behaviors and redirect their dog to an alternate activity/behavior," says Dana Ebbecke, behavior counselor at the American Society for the Prevention of Cruelty to Animals (ASPCA) Adoption Center.

"Pet parents should consult with a certified professional behavior consultant for help humanely modifying these behaviors. If there are common precursors to tail chasing (such as something stressful in the environment), they should anticipate these precursors and either change something in the environment to decrease the likelihood that the behavior will occur or begin training an alternate response to the stimuli that prompts tail chasing."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.