Cats Travel & Safety

Can Your Cat Safely Chase, Kill, or Eat Insects?

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Insects, from your cat’s point of view, are a great opportunity for a lively chase and hunt. Crawling insects can keep a cat entranced for hours, or minutes, if the cat decides to pounce and eat. If the bug has wings – even better. I’ve seen my cats gleefully leap, catch, and swallow countless flies.

Being a curious and prone-to-worry cat mom, I have often wondered if any of these bugs are harmful to kitties. What happens to your cat if she swallows a fly, or worse, a wasp? Is a fly “dirty” and does it carry disease? What if a cat ingests a poisonous or stinging insect? How can we as cat caretakers be prepared?

Harmless Insects

According to Georgina Ushi Phillips, DVM, gnats, flies, moths, and butterflies are generally harmless for cats to ingest. Insects with rigid exoskeletons (beetles and grasshoppers, for example) are considered non-toxic to cats, but could cause stomach upset if the cat overindulges in too many of these insects at a time. Some spiders are also harmless, but certain spiders are very harmful for your cat.

The Hunt vs. Ingestion

Dr. Phillips notes that cats like to play with their prey. Because cats like to take the time to play with a hunted insect, this can leave more time for the cat to be stung or bitten. If a cat engages with a venomous spider, for example, there’s more likely harm if the spider bites the cat than if the cat ingests the spider. Stomach acids can act to lessen or eliminate any harm from the ingestion of many insects.

Harmful Spiders

Phillips says the risk to your cat from venomous spiders is greatest during the hunt, when your cat may be bitten by the spider. The key is to be watchful for either cat/spider interaction or, if that isn’t possible, being aware of the appearance of a bite or signs of a bite.

Harmful spiders include the following:

Black widow: Research has shown that this spider, found everywhere in the world, will try at first to avoid an aggressive encounter. If the spider does resort to biting, it may inject venom or bite without venom (a “dry bite”). However, it will be difficult for you to determine if your cat was bitten, since the bite marks are small and difficult to discern under a cat’s fur. If you suspect a black widow bite, alert your veterinarian immediately, since black widow venom affects the nervous system and causes pain, cramping, uncoordinated movement, drooling, and vomiting in cats. These bites can be life-threatening.

Brown recluse: With a range in the southern U.S., this spider’s bite (which is large and visible to human eyes) causes severe necrosis in cats and is life-threatening if not treated. (Necrosis refers to tissue death.) Timely routine wound care will treat this bite.

Hobo spider: Located in the U.S. and in Europe, this spider’s bite, untreated, could lead to necrosis in your cat. If caught in time, routine wound care will treat this bite successfully.

Routine wound care doesn’t necessarily mean cleaning and treating it at home. Depending on progression of the wound, veterinarians will need to clip the fur around the bite and flush the wound with an antiseptic solution and sterile saline. In the case of severe bites, necrotic skin and tissue may need to be removed while the cat is sedated or under anesthesia.

Wounds from spider bites are typically left open to heal, Phillips says. Most heal within one to three weeks. Antibiotics may be prescribed if there is evidence of a secondary bacterial infection. Safe pain medications prescribed by the veterinarian are also an important part of recovery.

Roach and Flea Ingestion

If your cat ingests fleas (during grooming, for example), she can end up with tapeworms. Untreated tapeworms can lead to weight loss and diarrhea. Roaches also carry tapeworms and roundworms, which can be passed to your cat if she ingests the roach. Signs are weight loss and diarrhea.

Stinging Insects

These include bees, wasps, hornets, ants, and other stinging insects. It is usually unlikely that your cat will be stung while ingesting a stinging insect, since the cat is most likely to kill the insect before ingesting it. If your cat were to be stung inside the mouth, though, anaphylactic shock is rare in cats; pain and swelling are more common. Consult your veterinarian, who may treat with the antihistamine diphenhydramine. Cats may also infect a sting site if they lick it, which will require veterinary treatment.

Indoor Safety

Dr. Phillips points out that harmful cat/insect encounters are much less likely if you keep your cat inside. Keep cats away from dark, quiet areas of the house such as the basement or garage, where spiders and insects are most likely to be found. 

Be Prepared

Depending on where you live and whether your cat spends time outdoors, you’ll be contending with insects unique to your geographic area. Do your research and learn to recognize harmful spiders or other harmful insects (scorpions, for example) that might reside in your area of the world. Review the signs of a bug encounter gone bad for your cat, and be ready to act.

Dr. Philips recommends keeping diphenhydramine on hand at home to manage the effects of many stinging insects. Always consult your veterinarian first before administering this medication to make sure it’s appropriate for the type of bite and that you give a correct dose.

Establish a relationship with a primary veterinarian and an emergency veterinarian ahead of time. Be prepared so you know who to call, and what to report, should you suspect that your cat has harmful effects from being bitten by or ingesting an insect.  

This article was reviewed/edited by board-certified veterinary behaviorist Dr. Kenneth Martin and/or veterinary technician specialist in behavior Debbie Martin, LVT.

Catherine Holm is the award-winning author of cat fantasy fiction and cat-themed memoir. She lives in Minnesota with her husband and six well-loved cats. Learn more about her work at

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