Are Lightning Bugs Poisonous to Cats? (Fireflies)

Are Lightning Bugs Poisonous to Cats

Seeing a bunch of lightning bugs – aka fireflies – flying around in a clear night sky is a cool sight

But these little glow bugs pack quite the toxic punch. So, if you’re wondering; are lightning bugs poisonous to cats?

The answer is – Yes, they are

Lightning bugs possess a chemical that is very toxic when ingested. Small lizards and similar size animals can die from eating just one firefly, so it’s incredibly important that your cat does not eat lightning bugs.

They’re interesting little insects. If you want to more about them, the risks they present to cats, dogs, and other animals, and what to do if your cat eats one – please read on.

What Are Lightning Bugs and Where Are They Located?

What Are Lightning Bugs and Where Are They Located
Fireflies look very different in the daylight, don’t they!

Lightning bugs, also called fireflies are a soft-bodied beetle (Ladybugs are also part of the beetle family) that gets their names because they glow at night.

They do this because they have a chemical compound called lucibufagins in their lower abdomen. Lucibufagins might make them look cool by glowing at night, but it’s actually a defensive steroid that glows to warn predators that they are toxic.

Fireflies live in tropical climates and are usually found flying around wet wooded areas and marshlands. In the U.S the states with the most fireflies are Pennsylvania, Florida, and South Carolina.

There are some 2,000+ species, and they can differ in size and appearance quite a bit. There’s no mistaking the glow they emit at night though. In some parts of the world, they’re simply called “Glow worms”, or “Glow bugs”.

If you come across them you don’t need to be concerned about being harmed. They don’t attack humans or pets. Their defensive mechanisms are designed to warn off predators and do harm to anything that tries to eat them.

Related ContentIs it OK for cats to eat centipedes?

Can Cats Eat Lightning Bugs?

There’s good and bad news. The bad news is that lightning bugs are actually very toxic to cats. As well as dogs, other small animals, insects, and any living thing that thinks it’s a good idea to eat them.

The good news is that it’s very difficult for a cat to catch and eat a firefly, so it’s very unlikely they will eat one. Even if you have them in the area where your cat roams and hunts.

It’s lizards and birds that prey on these little insects the most. They regret doing so shortly after as firefly toxicosis is fatal to small reptiles, animals, and birds as I’ll explain in more detail below.

It’s difficult to control what your cat chases and eats while outside roaming. But, fireflies are so toxic it’s worth doing everything you can to ensure your cat’s exposure to them is minimal.

What Happens If a Cat Eats a Firefly?

Can Cats Eat Lightning Bugs
Don’t do it, I’ve just explained how toxic they are!

Investigating this topic I found a couple of accounts from cat owners saying their cats attempted to eat a firefly but quickly spat it out when they tasted it. I also spoke to a friend that said the same thing.

Apparently, fireflies also taste and smell foul (I’m not going to find out first hand). This is a good deterrent if your cat does manage to catch one.

Plus, one firefly shouldn’t be enough to cause serious harm to a cat or be fatal. Although, one is toxic enough to cause some gastrointestinal and motor issues. The toxin actually affects how an animal moves and thinks by disabling an enzyme that transports ions across cell membranes.

Fireflies really do pose a serious toxic threat to any animal that eats them.

Although we’re fortunate enough not to know much about what happens when a cat eats a firefly, we do know what happens when a lizard eats one.

Bearded dragons find them hard to resist and are much better at catching them. If they eat a lightning bug, they start shaking within 15-20 minutes as firefly toxicosis sets in. They will retch and vomit as the horrible taste registers and they become aware of the ill effects – and can be dead within 2 hours.

It’s that fast.

In Summary – Are Lightning Bugs Poisonous to Cats?

Lightning bugs, fireflies, glow bugs or whatever you call them where you live are poisonous little insects.

The chemical compound that creates the glow in their lower abdomen is called lucibufagins. This compound is toxic, and when ingested is powerful enough to kill a small lizard within a couple of hours.

Fortunately, there aren’t many known cases of cats eating fireflies as they’re hard to catch. But it’s certainly worth keeping in mind how toxic they are if you have any small pets that might come across them.

What’s your experience with lightning bugs? Has this information come as a surprise to you? Did you know how toxic these little critters were?

10 thoughts on “Are Lightning Bugs Poisonous to Cats? (Fireflies)”

  1. Shannon Hensley

    My male 1 yr old ginger cat just ate a firefly it was in the house I seen him grab and eat it its been about 5 min so far he’s ok im little freaking out tho. I’m worried about him after reading this. I will be back if something goes bad with my kitty.

    1. How’s your cat? Mine just tried to eat one but he did not cate for the taste at all and luckily spat it out.

    2. Our cat just ate one too! It freaked me out so much….. she ran around the house and spit out a white foam a few times and is now laying down. I’m definitely keeping a close eye on her! I had no idea how toxic they were. We usually don’t see them until August….

  2. Yeah I saw my cat out chasing fireflies one summer evening, he wasn’t much more than a year old and it was the first real massive firefly show in a few years as well, and not know the danger I wasn’t the least bit concerned. After much jumping and chasing I saw he’d finally caught one and, as he tended to do with any bug (house flies especially) he began to chew it up like a nice little evening snack.
    Then suddenly he stops chewing and he immediately tries to spit it out, but being mostly masticated by then seemed to make it very difficult, I could see his tongue working furiously to eject it, so I called out, “What’s the matter Schrodinger, too spicy?”
    But then he began to drool, just a little at first shaking his head back and forth, backing away, even stood up on his hind legs as if that would help, and by then the DROOL was crazy, I mean I’d never seen anything like it, just long strands of it, and it went on for a couple of minutes before I got over my fascination and realized he was really miserable. So I rushed over and grabbed him and ran into the house, took him to the sink and ran some cold water, rinsed his mouth out and let him lap up some.
    Afterwards he seemed a little woozy but okay, and I still had to laugh when he followed me back out to the porch but rather than run out into the yard as he normally would, he just sat next to me, looked out at the fireflies and just mewed a kind of growly sound.
    I could tell he was having to make a major shift in his world view of all bugs as nature’s tasty treats put there for his own personal enjoyment, lol, tough lesson to learn. But from this experience I don’t think that there’s any danger that ANY full grown healthy cat would ever get past trying just one and that doesn’t seem to be lethal, barring allergic reactions or other health issue (maybe small kittens perhaps).
    So I think people can rest assured and not panic if your cat’s out chasing fireflies on a summer night, cuz if it’s in their nature, they like the hunt, the chase, and after this experience I know my cat, while he still enjoyed hunting and killing bugs, eating them seemed reserved for just a familiar few, like flies and crickets ;?)

  3. If you’ve just witnessed your cat ingest a firefly and are sure it was just ONE and not more(and managed to not puke all over), first step would be to monitor the cat. Take it 10 minutes at a time, up to an hour. If they show signs of distress, or abnormal behavior, call your vet. You may feel the need to do so immediately, but, more than likely, they will tell you to monitor and call back if distressed, before bringing in. The size/age of your cat will play a significant part in how they handle ingesting a lightning bug. More than likely, they will vomit it back up and never do it again! If you’ve ever splatted one and actually smelled the toxic “glow” fluid..pretty fowl! But if you’re absolutely panicked and can’t stand waiting, you’re vet is only a call away!

    1. My cat, 22 months old, caught & ate a firefly tonight. Well, she also started foaming at the mouth & spit it out. Idk why the author said they were so hard to catch – she proceeded to catch at least three more! (She jumps high in the air & can grab them – she’s always been an incredible jumper.) I had her out on a leash & harness, so every time she caught one, I’d move her away from it. I think she’s kind of a ditz – after the foaming at the mouth incident, she still wanted to eat them. Thankfully, she’s acting totally normal now that we’re inside & it’s been 30min since she ate that one.

  4. I’m glad I read this before letting my cat eat one. It was laying on the floor and she likes to play with her food before she eats it, so she just left it alone and sometimes hit it. I decided to check and see if it was any bad for her and I’m glad I did. I killed it and disposed of the body once I had done it. 🙂

    1. My 4 mo old kitten caught one last night! Immediately she tried to spit it out and I could tell she was not ok! I rushed to her and she was foaming at the mouth. I rinced out her mouth and she drank quite a bit of water! I wad in the backwoods of an Arkansas lake miles from anywhere at all! I had no idea they were poison! I grew up in the north woods and they were everywhere! Clearly now ! Kitten is only 3 lbs and is ok this morning! I will closely watch her!
      Never out in the evening again. She was on her Leash and harness btw.
      Thanks for this blog

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