Why Do Dogs Hate Flies?

Adrienne Farricelli

Dogs hate flies for a simple reason: flies are annoying pests and dogs seem to despise them just as much as we do. We can't blame them though, deprived from having hands, dogs are pretty much at the mercy of these buzzing, pesky creatures. These leaves them with only one option: attempting to catch them with the power of their jaws.

Dogs hate flies with a passion and some of them may even act panicky  as soon as they hear one buzzing around. What's up with these dogs? Can dogs develop a phobia of flies?  Why are dogs so worried about them? Turns out, this instinct is an adaptive trait after all, considering that, allowing  bugs to land on them and make themselves at home may lead to significant trouble down the road. 

A Matter of Prey Drive 

Countless dogs will try to chase and snap at the flies with loud clacking sounds coming from their jaws. Courtesy of the flies' great maneuverability in flight, most flies are capable of surviving these near death encounters. 

Fact is, dogs are attracted to anything that moves. Dogs therefore chase flies for the same reason why they chase their neighbor's cat, a squirrel up a tree or that ball moving in an unpredictable pattern that you toss him to fetch every day. It's all a matter of prey drive. 

Prey drive in dogs is something complex but overall quite intriguing. Clarissa von Reinhardt in her book "Chase, Managing Your Dog's Predatory Instincts" describes prey drive in dogs as a natural instinct, something that is passed down by genes but also shaped for a good extent during early development and learned in part by imitation.

Flies, are in particular, are quite intriguing for dogs to chase. Perhaps a big role it s the fly's unpredictable flying patterns. Flies indeed tend to fly in a straight line and then once they detect Rover's intent, they'll make a rapid change in direction.

  Of course, it goes without saying that dogs wouldn't be attracted to chasing and trying to bite flies if they weren't as annoying as Nature made them.

The Annoyance of Flies  

Yes, we're talking about the common fly Musca domestica, the house fly, and Musca vetutissima, the bush fly. Studies say that this latter type of fly is the one most attracted to people and animals, while the house fly is more interesting in things they find in our homes. 

In particular, the bush fly has a reputation of having fleshy mouth parts meant suck up  secretions found on the skin, just like a sponge. In dogs, equipped with a lot of hair, they are more after to landing on their eyes and hairless areas,especially nearby their bum which often smells like poop.

Dog poop indeed ranks high as one of the flies favorite thing. It serves a dual purpose, a tasty smorgasbord and the perfect egg depository. While dogs are not aware of this, they sense flies as natural enemies. 

Unlike us who though who can shoo, swat and swear, dogs are only left to their own devices: once again, they rely on their mouths to try to send them away. 

A Natural Instinct

Mother Nature must have equipped dogs with a natural instinct to avoid flying instincts for a good reason: they can wreck havoc on a dog's health. 

Of course, not all flying instincts are harmful, but your dog will never turn into an entomologist, that is, a scientist who studies insects professionally, so he'll just play it safe and send any buzzing critters away. 

What flies though are problematic? And what can these flies do to a dog's body? If you are not too squeamish, read on for the risks certain types of flies pose to dogs. Rest assured though, after reading these problems, you may not see flies as innocent as before. 

An Enemy to Fight 

On top of being annoying, as mentioned, flies may pose some dangers to Fido. Here are some health conditions in dogs associated with flies. 

A certain type of fly, in particular, the stable fly, (stomoxys calcitrans), is known for targeting a dog's ears, biting them and causing a condition that is known as fly strike dermatitis. This condition is common in outdoor dogs. The more the flies bite, the more the blood draws other flies, leading to an ongoing problem. 

Other flies, in this case, the common houseflies, and the bluebottle flies, may also lay eggs on open wounds and any fur caked with urine and feces. These flies typically impact sick or elderly animals who struggle to easily reach their backsides. 

These eggs, once deposited, develop into larvae known as maggots. Left untreated, dogs with maggots risk suffering from serious damage as the larva continue to feed on necrotic, dying tissue. 

And then, we must consider that other types of insects that fly can also harm dogs due to their painful stings as it happens with bees, wasps and hornets. 

A Phobia of Flies 

Many dogs seem to have a phobia of flies. My dog would go crazy if she happened to be around flies and would be unable to concentrate until we grabbed the fly swatter and killed the fly for good. 

Perhaps, she was stung as a puppy and this led to a particular phobia of any flying insects that never disappeared for over 10 years despite thousands of safe encounters during her lifespan. 

For some reason, many dogs seem to get particularly upset if the fly ends up too close to their bums. I attribute this to the fact that unlike horses, dogs don't have a highly mobile tail they can use to swat them away, plus the area is difficult for them to reach and look at. Hence, why many dogs are so eager to have their bums scratched by us. 

On top of this, most of a dog's private areas lacks hair, and perhaps this makes dogs instinctively protective of them.

Now That You Know....

As seen, dogs hate flies for several good reasons! Next question though is, what can be done to stop flies from pestering dogs? And how can dogs with a phobia of flies be helped? Here are some tips!

  • Keep your dog inside. Flies are less likely to bother dogs if dogs are kept inside.
  • Use fly traps. Many stores sell these and they can help reduce the numbers of these pesky bugs. 
  • Try fly repellents. Fly's Off by Farnam is a special mist that can be used to repel flies, gnats and mosquitoes away from dogs. Some dog owners have also found that applying Avon Skin So Soft can help repel a variety of bugs including flies. 
  • For flies depositing eggs, the goal of treatment is to keep the affected area clean and the flies off so that they don't have the opportunity to lay eggs. 
  • For fly phobias, it helps to do as much as possible to prevent flies from being around your dog. Sometimes you can desensitize and counter-condition dogs by gradually exposing them to flies and creating positive associations with them. In other words, every time there is a fly nearby, you would feed your dog a treat until your dog starts acting calmer around them and looking forward to a treat. However, this may not be easy to implement, considering that flies may be around when you are not present. 
Comments (2)
No. 1-1

Thank you for this. My dog is incredibly scared of flies - if he sees one inside, he will hide in the closet for the rest of the day, even if I catch it and remove it. It's good to know that he's not the only one. I already catch them as soon as I see one and have fly traps set up, but I'll try the positive conditioning method too.

1 Reply

Adrienne Farricelli
Adrienne Farricelli


So sorry to hear your dog is so scared of flies! My Rottweiler was bothered by flies too, but she would plead me to catch them and kill them for her. Only until then, she could calm down and go back to a relaxed. I hope the positive conditioning method works for you! Best, Adrienne