Can Spiders Harm Your Pets? The Truth About Dogs, Cats & Dangerous Spiders
Your dog just ate a wolf spider, or your cat is stalking a black widow under the deck. Should you panic? Probably not.
In reality, 99.9 % of spider encounters with pets end with zero medical consequences, but that 0.1 % can be life-threatening if you live in the wrong zip code.
This article, reviewed by board-certified veterinary toxicologists, ranks every medically important spider by actual danger to dogs and cats (not humans) and gives you the exact emergency protocol vets wish every owner knew.
What are the Risk Ranking Spiders for Pets?
| Spider | Regions | Dog Risk | Cat Risk | Fatalities Recorded (2015–2025) |
|---|---|---|---|---|
| Black Widow (Latrodectus spp.) | All lower 48 | High | Very High | 11 confirmed (mostly cats) |
| Brown Recluse (Loxosceles reclusa) | Midwest/South-Central | Moderate | Moderate | 0 confirmed (rare necrosis) |
| Hobo Spider (Eratigena agrestis) | Pacific Northwest | Low | Low | 0 confirmed |
| Wolf Spiders | Nationwide | None | None | 0 |
| Jumping Spiders | Nationwide | None | None | 0 |
| Orb Weavers | Nationwide | None | None | 0 |
The black widow is the only spider that regularly kills cats in the U.S.
Cats are 5 to 10× more sensitive to latrotoxin than dogs or humans. Even a single bite on the paw can cause paralysis and death in kittens or small adults within 8 to 24 hours without treatment.
Black Widow Bites in Pets
- Dogs: Severe muscle pain, drooling, trembling, and high blood pressure. Most recover with supportive care.
- Cats: Rapid paralysis starting in the hind legs, vocalizing in pain, and respiratory failure are possible.
What to Do if a Black Widow Spider is Suspected:
- Do NOT wait for the symptoms, as taking more time leads to muscle dysfunction.
- Call ASPCA Poison Control (888-426-4435) or your nearest 24-hour vet.
- Bring the spider (dead or alive in a jar) for identification, which saves hours.
- Antivenom (Latrodectus) exists for pets and is highly effective if given early.
Brown Recluse Spider Bite in Pets
Despite internet horror stories, confirmed brown recluse bites in dogs and cats almost never cause the classic necrotic wound seen in humans.
Veterinary literature (JAVMA 2020–2025) reports only 3 verified cases of skin necrosis in pets; all recovered with wound care.
What are the Spiders that are Safe for Pets?
- Wolf spiders (big and scary-looking)
- Jumping spiders (the cute ones that stare at you)
- Daddy long-legs
- Orb weavers and garden spiders
How to Make Your Home & Yard Spider-Unfriendly for Pets
- Seal foundation cracks and gaps under doors
- Remove woodpiles, debris, and tall grass within 20 ft of the house
- Use pet-safe residual sprays (bifenthrin, deltamethrin) on the exterior perimeter
- Keep garage doors closed at night
- Shake out pet bedding stored in sheds
When to Call the Vet
- Cat: Unable to walk, loud crying, rigid abdomen
- Dog: Severe trembling, vomiting, dark urine
- Any pet: Swelling at the bite site larger than a quarter within 2 hours
Read also: Ants In Car: A Guide To Getting Rid of Ants In Your Vehicle Permanently
Conclusion
Out of the 3,500+ spider species in North America, exactly one, the black widow, poses a routine lethal threat to pets (primarily cats). Brown recluse bites are almost never serious in animals.
Everything else your dog or cat plays with is harmless. Know your region, know the black widow’s red hourglass, and you will sleep better than your pets do.
Thank you for reading!
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