Sky Raisins: Why Pets Eat Flies (and Is It Safe?)

A dog sniffing the camera lens.

Household flies are a nuisance for many of us, especially in the summertime. But when it comes to our pets, these sky raisins are particularly interesting.

You have probably seen your cat or dog swat or chomp at flies, and, of course, gobble them up like they are a tasty snack. Since cats and dogs are instinctual hunters, this tiny prey may seem like an easy bit of nutrition for them, even though it is gross to us.

The question we at Rocklin Ranch Veterinary Hospital often get from pet owners is why pets eat flies and is it safe for them to do so. You are in luck. We are here to explain this airborne fixation for your best friend.

Why Do Pets Eat Flies?

Along with their drive to catch prey, many cats and dogs simply enjoy the challenge of catching flies. It is a mild form of amusement or enrichment for them. If your pet gets bored easily or has a lot of energy, this pastime can help them feel like they are doing something. 

Cats have a hardwired hunting instinct, so for them, catching flies is akin to any other prey, like mice and birds. Hunting flies and other insects can alleviate frustration and boredom if your pet isn’t getting enough exercise, or has anxiety or stress.

Just because your pet eats sky raisins doesn’t mean that they need to eat more food, however. This behavior likely has more to do with their instinct and idea of a good time than their caloric intake. So, there is no need to top off the food bowl (even though your pet wouldn’t mind, the scale may say otherwise). 

Is Eating Flies Safe for Pets?

For the most part, if your pet eats a fly, it is probably nothing to worry about. While it is true that flies carry dozens of diseases that are transmittable to humans, as well as bacteria and parasites, the acidic contents of the stomach kills most bacteria. 

There are some accounts of toxicity from eating flies who have been doused with insecticide, which is why using pet safe bug spray is the best option. If you spray a fly with a chemical, quickly clean up and remove the insect right away. 

Off-Limits Insects

Not all insects are okay for your cat or dog to eat. Some can cause symptoms from gastrointestinal distress to venom toxicity. Make sure to keep your curious cat or canine from chomping the following insects.

Caterpillars: Though these slow moving insects seem pretty safe, some species can cause harm. Certain caterpillars, those that develop into Monarch butterflies, contain the toxin cardiac glycoside which is poisonous to pets. Other species have hooked stingers and spines that are painful when bitten down on.

Stink bugs: The name even sounds like a no-go when it comes to cuisine. Stink bugs cause stomach ache, vomiting, and diarrhea in some pets.

Asian Lady Beetles: These creatures can do damage to a pet’s mouth, throat, and GI tract, causing severe burns from the protective chemicals in their bodies. 

Snails, slugs, and earthworms: These innocuous looking gooey animals can actually transit lungworm to pets if ingested.

Ladybugs: Ladybugs contain a substance that is discharged when a pet eats them causing ulcers of the mouth and tongue.

Wasps and bees: Obviously, if a pet eats them they can be stung on the mouth and lips. If a pet gets too close to a nest, this can result in a severe or sometimes fatal number of stings.

Spiders: While there are many spiders that are harmless, the brown recluse and black widow can inject their venom, which can prove to be life-threatening. 

Cockroaches, mosquitoes, and fleas: These troublesome insects cause infestation and carry with them a wide range of parasites and disease. 

In summary, a few flies ingested by your furry loved one may not be such a bad thing. After all, they seem to enjoy it. The only caveat is to keep them from ingesting more than one or two, and to keep these more serious insects out of the home and your pet’s mouth. This is another good reason for careful supervision when outdoors with your pet.

For more information on why your pet eats flies, or to schedule an appointment, please call us! We look forward to seeing you and your beast-y bestie soon.