Why Does My Dog Chase Flies? (7 Common Reasons)

Categorized as Why Does My Dog
dog chasing flies

Dogs love to chase things. It’s in their nature. And for the most part, this is perfectly normal behavior. But sometimes, a dog’s chasing behavior can be excessive, to the point where it becomes a problem.

One common example of this is when a dog becomes obsessed with chasing flies.

There can be a number of reasons why your dog might like to catch flies. In this article, we’ll explore seven of the most common reasons.

1. Flies Can Sometimes Trigger a Predatory Response in Hunting Dogs

Most dog breeds were originally bred for specific purposes, and hunting is one of them.

Hunting dogs are hunters by nature and their prey drive is strong. This means that they have a natural instinct to chase and kill smaller animals.

For some hunting dogs, the sight of a fly can trigger this predatory response. They see the fly as a potential prey item and they want to catch it.

Common examples of breeds with high prey drives include the following:

  • Greyhounds
  • Lurchers
  • Collies
  • Terriers

However, it should be noted that any dog can have a strong prey drive although it is more common in hunting breeds.

If your dog is always on the lookout for potential prey items, whether that’s birds, squirrels, or even leaves blowing in the wind, then they probably have a strong prey drive.

2. It Could Signal an Obsession or Compulsive Disorder

Sometimes, a dog’s fly-chasing behavior can be a sign of an underlying obsession or compulsive disorder.

Dogs with Obsessive-Compulsive Disorder (OCD) become fixated on certain objects or activities. They feel the need to perform these activities over and over again, even if there’s no real reason to do so.

For example, a dog with OCD might chase their tail obsessively or lick their paws excessively.

Fly-chasing can be a form of this type of repetitive behavior. The dog becomes fixated on the flies and feels the need to chase them, even if there’s no real reason to do so.

Veterinarians don’t yet agree on what causes OCD in dogs. It might be due to a chemical imbalance in the brain or it could be the result of genetics, upbringing, or environment.

Regardless of the cause, OCD in dogs is a real condition that has become common in recent years. If you think your dog might have OCD, it’s important to take them to see a veterinarian so they can get the help they need.

3. They Might Be Bored

Another common reason why dogs chase flies is because they’re bored.

Dogs are active creatures. They need to be given plenty of exercises, both mental and physical.

If a dog isn’t given enough to do, they can become bored. And when they’re bored, they often start to engage in destructive or nuisance behaviors like chewing on furniture or chasing flies.

If your dog is always chasing flies, it might be a sign that they need more to do. Try giving them more toys to play with, more interesting chew objects, and more opportunities to exercise.

You might also want to consider enrolling them in a dog training class. This can provide them with much-needed mental stimulation.

4. Dogs Could Be Attracted to the Movement of Flies

Dogs are attracted to movement. This is why they like to chase things like balls and Frisbees.

The same thing goes for flies. Dogs see the fly moving and they want to chase it.

This is especially true for young puppies who are still exploring the world around them. They’re curious about everything and they want to chase anything that moves.

5. Your Dog Might Experience a Mild Form of Seizure

There is very little evidence to prove or disprove this theory.

However, some experts believe that dogs could be chasing flies because they’re experiencing a mild form of seizure. This is known as complex partial seizures or focal seizures which manifest hallucination-like symptoms.

During a complex partial seizure, your dog might appear to be staring at something that isn’t there. They might snap repeatedly in the air as though they’re surrounded by flies.

While there’s no concrete evidence to support this theory, it’s something that you should be aware of if your dog constantly seems to be chasing flies.

6. Your Dog Might Have an Eye Condition Called Vitreous Floaters

If your dog is constantly trying to catch flies but never actually manages to catch one, they might have an eye condition called vitreous floaters.

Vitreous floaters are small pieces of debris that float in the vitreous humor, the jelly-like substance that fills the inside of the eye.

They’re usually invisible to the naked eye but can become more apparent when you look at something with a lot of contrast, like a white wall or the sky.

Dogs with vitreous floaters might think they see flies constantly flying around them. They try to catch the flies but can never seem to succeed because, of course, the flies aren’t really there.

7. Your Dog Might Have a Gastrointestinal Issue

In a recent study conducted at the University of Montreal Veterinary Teaching Hospital, it was found that five out of seven dogs with gastrointestinal issues also had experienced fly snapping behavior.

After receiving treatment for their gastrointestinal issues, the fly snapping behavior resolved itself in all five of the dogs.

This suggests that there might be a link between gastrointestinal issues and fly snapping behavior. If your dog is constantly trying to catch flies, it might be worth taking them to the vet to see if they have any underlying health issues.

Should You Be Concerned If Your Dog Is Chasing Flies?

Depending on the underlying cause, fly snapping behavior might be something that you need to be concerned about.

If your dog is chasing flies because they want to play, then there’s no need to worry. However, if your dog has never exhibited this behavior before and suddenly starts chasing flies followed by other strange behaviors, it might be a sign of a more serious underlying issue.

3 Tips To Stop Your Dog From Chasing Flies

If you’re concerned about your dog’s fly snapping behavior, there are a few things you can do to try to stop it.

1. Keep Your Dog Stimulated

If your dog is chasing flies because they’re bored, the best thing you can do is to keep them stimulated both mentally and physically.

Make sure you’re giving them enough exercise and providing them with plenty of toys and puzzles to keep their minds active. You may also want to consider enrolling them in a dog training class.

2. Provide a Distraction

If you see your dog starting to chase flies, provide them with a distraction. This could be a toy, a treat, or even just yelling their name to get their attention.

The goal is to get their attention focused on something else so they’re not as fixated on the flies.

3. Bring Your Dog To The Vet

If your dog has never exhibited this behavior before and suddenly starts chasing flies, it’s a good idea to bring them to the vet to rule out any underlying health issues.

As mentioned above there are three potential medical causes of fly snapping behavior: obsessive-compulsive disorder, seizure, eye problem, and gastrointestinal issues.

There are a few different options when it comes to treating obsessive-compulsive disorder in dogs. The most common treatment is behavior modification therapy, which involves teaching your dog new behaviors to replace the obsessive ones. This can be done with the help of a professional dog trainer or behaviorist.

There are a few different options when it comes to treating seizure disorders in dogs. The most common treatment is medication. Dogs with seizures can be given anti-seizure medication to help prevent or reduce the frequency of seizures.

Surgical intervention is the most common treatment for vitreous floaters. During the surgery, the vitreous humor is removed from the eye. This procedure is called a vitrectomy.

The best way to treat gastrointestinal issues will depend on the underlying cause.

If the cause is a food allergy, your dog will need to be placed on a hypoallergenic diet. If the cause is an infection, your dog will need to be treated with antibiotics. If the cause is inflammation, your dog will need to be treated with anti-inflammatory medication.


Dogs are often fascinated by flies and will chase them, which is an interesting behavior. The article has some tips to try if your dog exhibits this behavior. If you’re concerned about your dog’s fly snapping behavior, it’s a good idea to bring them to the vet to rule out any underlying health issues.

Related Questions

1. Why Does My Dog Chase Cars All of a Sudden?

There are several reasons why a dog might start chasing cars. The most common reasons are curiosity, a strong prey drive, and playfulness.

By Andrew Garf

Andrew Garf has loved dogs, especially German Shepherds, since he was 10 years old. Though he also loves burgers, training dogs is his real passion. That's why he created the website TrainYourGSD.com - to help dog owners learn how to properly train, care for, and bond with their German Shepherd dogs.