My Cat Was Bitten by a Spider, What Should I Do? (Vet Answer)

Cats are natural hunters. This instinctual behavior has been retained from their ancestors who had to hunt frequently to satisfy their need for a carnivorous diet. This drive is practically insatiable in many of our modern housecats whose interest can always be piqued by an animated cat toy running across the floor.

In terms of actual hunting, indoor-only cats will not likely come across the many rodents or small mammals their outdoor-dwelling counterparts might pursue. Thankfully, our homes are pretty good at keeping those critters outside. Despite our best efforts, however, the odd fly, ant, or spider might still manage to gain access. The tiny stature and quick, darting movements of these insects is enough to trigger the feline hunting reflex and most housecats will respond with great gusto. They quickly go into hunt mode; chasing, catching, and eating. Unfortunately, some of these insects- particularly spiders- can bite back and may even be venomous!

Which Spiders Are Dangerous to Pets?

In the United States, the two spiders that are of most concern are the Black Widow and the Brown Recluse. Most other spiders you find in your home might be able to deliver a bite but will not be capable of injecting enough venom to hurt a cat. Check your local authority for which spiders might be of concern in your own geographic location and how to identify them.

Black Widow Spiders

Black widow spiders are 1 inch to 1.5 inches in length. The males are smaller than the females and are brown in color with pink or red spots and a beige stripy pattern, depending on the species. Female Black Widows are more distinctively patterned with a jet-black body, bulbous abdomen, and oftentimes a red hourglass shape on their underside.

Thankfully, the Black Widow is not naturally aggressive and won’t bite unless provoked. Even when this spider does give a nip, there will not necessarily be any venom released in the bite. Spider venom is energetically costly to produce so a spider will conserve it as much as possible. A venomous bite will normally only be given during hunting or when the spider feels that its life is being threatened. In a scientific study, even when Black Widow spiders were pinched to invoke an aggressive response, more than half of the interactions were met with a dry bite where no venom was released.

With all this being said, a cat in pursuit of a running prey is unlikely to respect the boundaries of a dangerous spider- even after non-venomous warning nips are given.

Brown Recluse Spider

The Brown Recluse was given its name for a reason; it really is a reclusive spider. These 8-legged critters are nocturnal and will spend most of their time hiding away in an undisturbed spot. This spider is normally around half an inch to an inch in length, brown, and can be identified using the violin-shaped dark patch on its back. It is also unique in that it has six eyes in three paired clusters on its head rather than having eight eyes as most spiders do.

Not only is this spider reclusive, but it is also very non-confrontational. In a case study investigating a Kansas home infestation of over 2000 Brown Recluse spiders, no bites were received by any of the four occupants during the five and a half years of living there despite frequently crossing paths with the spiders. In fact, venomous Brown Recluse bites are so rare that many researchers believe that many supposed bites have been misdiagnosed. Similar to the Black Widow, a Brown Recluse will only bite as a final effort to escape a predator that is endangering its life.

What Should I Do If My Cat Is Bitten By a Venomous Spider?

If your cat is bitten by a venomous spider, it is unlikely that you will be present during the event. You might see the sign of a bite on your cat’s skin, but it will probably be buried in the fur or hidden in the mouth if your cat decided to try and take their prey as a snack.

If you do happen to catch the spider bite in the act, remove your cat from the situation so they can’t be bitten again. Since most bites are not venomous, even from a venomous spider, you can monitor your cat closely over the next 24 hours for any signs of toxicity and be ready to bring your cat into the emergency room at the first sign of any symptoms.

Even if you haven’t experienced any venomous spider threat, you’ll want to watch out of the symptoms of envenomation which, on their own, are reason enough to be concerned about your cat’s health.

How Can I Tell If my Cat has Been Bitten By a Spider?

The Black Widow spider’s venom is made up of a neurotoxin that causes neurological symptoms of toxicity. Soon after a bite, you may notice excessive salivation, vomiting, or drastic changes in behavior which indicates pain in a cat. You’ll want to bring your cat to the emergency veterinarian if you notice these occurring for longer than a few hours at a time. These signs can escalate to loss of coordination and paralysis which are always a grave cause for concern. If you notice these symptoms in your cat, take him to an emergency veterinarian immediately.

The venomous bite of a Brown Recluse spider most often targets the skin where the bite was given. The venom causes tissue death which can cause varying degrees of redness, swelling, rashes, or blisters around the bite. Sometimes this can lead to systemic effects which can manifest as loss of appetite, extreme lethargy, and pain. Again, if you see these symptoms in your cat for more than a few hours, bring your cat in to see a vet as soon as possible.

What Will the Vet Do If My Cat Was Bitten By a Spider?

Your veterinarian will create a treatment plan depending on your cat’s symptoms, the severity, and the likely culprit for the bite. The plan can include the administration of intravenous fluids, use of supplemental oxygen, pain medication, administration of anti-venom, and ongoing monitoring. If treatment for a venomous bite is sought on time, the prognosis is generally quite good.

Is There a Way to Prevent Venomous Spiders From Getting Into My Home In the First Place?

It is possible to reduce the likelihood of any spider making its way into your home. Vacuuming regularly will keep the home tidy and less hospitable to other insects which may attract a hungry spider. A home can also be spider-proofed by filling in holes and gaps along the walls which can lead outside. Additionally, eliminate anything around the house in which a spider may choose as a shelter. Piles of wood, for example, tend to be a place where spiders shelter or choose to make their home.

Frequently Asked Questions About Spiders and Cats

Is it ok if my cat eats a spider? Can cats die from eating spiders?

Your cat is unlikely to die or get sick by eating any house spider, even a venomous one. If your cat has not been bitten, any venom in a spider’s body will be neutralized through the digestive process. A spider’s venom is meant to be injected into the bloodstream to exert its toxic effects. However, it is possible for your cat to get bitten on the inside of the mouth, so if you live in an area with venomous spiders you should know the signs that your cat has been bitten by a spider.

Are Daddy Long Legs spiders and Wolf Spiders dangerous to cats?

Both the Daddy Long Legs spider and Wolf Spider may look intimidating, but they don’t pose a threat to your cat. The venomous bites these spiders give are enough to take down an insect prey item, not a potential predator many times their size.

Conclusion

Hopefully, your cat never goes head-to-head with a venomous spider. It is difficult for a natural predatory animal to turn the other cheek, so something scurrying across his territory will be nearly impossible to ignore! Thankfully, spiders will only use a venomous bite as a last resort and now you’ll know what signs to look out for if you suspect that your four-legged friend was given a toxic nip.

Featured Image: Andre Mueller, Shutterstock