Cats love to play with bugs, and it might be difficult for your cat to resist teasing a creepy-crawly spider. However, there are some extremely poisonous spiders in Arizona, and their venom could be deadly if they bite your cat. Outdoor cats aren’t the only ones at risk of spider bites—if a venomous spider finds its way indoors, house cats could get poisoned from a spider bite as well. 

Spider bites in cats are always an emergency! A little bit of knowledge and swift action could save your cat’s life. The vets at East Valley Animal Hospital want to help you recognize which spiders are poisonous to cats, and familiarize you with the symptoms of a spider bite. We put together the following guide so you can keep your cat safe.

Poisonous Spiders In Arizona

Bites from spiders and other venomous creatures like snakes and scorpions can be fatal to pets, especially cats. Compared to dogs and humans, cats are much more vulnerable to spider bites, and also more likely to provoke a spider into biting. 

In Arizona, there are two types of spiders whose venom is poisonous to cats:

Black Widow Spiders

Black widows and cats are a dangerous combination. A bite from a black widow can cause respiratory paralysis, leading to death. Cats bitten by black widows will need an immediate anti-venom treatment, along with anti-seizure medications, muscle relaxants, IV fluids, and pain relievers.

Brown Recluse Spiders

Unless the cat gets veterinary treatment right away, a bite from a brown recluse can cause severe liver and kidney damage, and even death. 

How to Identify Spiders That Are Poisonous to Cats

Due to their small size and tendency to hide, it can be difficult to identify poisonous spiders. If you find a spider in your home or yard, here are some of the characteristics to look for:

  • Black widows range in size from 1.5cm to 2.5cm, and are shiny and black with a red or orange hourglass-shaped mark on the underside of their abdomens. They like warmth and typically hide in dark, secluded places like woodpiles, garages, and basements. Although they are nocturnal, black widows spin their webs during the day. They will usually “play dead” at first when they’re disturbed.
  • Brown recluse spiders measure between 8mm and 13mm, have long legs, and a violin-shaped mark on their upper bodies, just behind their eyes. They have three pairs of eyes, which distinguishes them from other small, brown spiders. Also nocturnal, brown recluse spiders that find their way indoors tend to hide in dark places like attics and basements, underneath rocks, or inside of dead cactuses.

Spider Bite Symptoms in Cats

If a black widow bites your cat, symptoms can include:

  • Severe muscle pain, cramping, and rigidity
  • Lack of coordination
  • Tremors
  • Paralysis
  • Drooling
  • Vomiting
  • Diarrhea

If a brown recluse bites your cat, symptoms can include:

  • Vomiting
  • Lethargy
  • Fever
  • Bleeding or bruising at the site of the injury

Emergency Vet in Gilbert, Arizona

If you suspect that your cat was bitten by a poisonous spider, do not hesitate! Come in immediately or call East Valley Animal Hospital at 480-568-2462. We can administer the antidotes and treatments your cat needs to make a full recovery. We are here for you each week from 7:30 am to 5:30 pm Monday-Friday, and from 8:00 am to 1:00 pm on Saturdays. 


Photo by Timothy Dykes on Unsplash used with permission under the Creative Commons license for commercial use 04/04/2022.