Spider Bites in Cats

Cats are prone to spider bites due to their inquisitive nature. Most spider bites are more painful than they are dangerous, however, there are a number of spiders which are venomous to cats.

Spiders venomous to cats:

  • Latrodectus (Widow spiders) – Worldwide distribution, well-known species include the Black Widow, Western Black Widow, Northern Widow, Red Widow, Brown Widow (USA), Katipo (New Zealand) and the Redback (Australia).
  • Hobo spider – Europe to Central Asia, United States and Canada.
  • Brown recluse – Found in the USA, the bite from this spider is necrotizing, killing off tissue around the area of the bite.
  • Tarantulas – Some species of tarantula can be toxic to cats.

Is the funnel-web dangerous to cats?

The funnel-web (found in Australia) is toxic only to primates (including humans) and not cats.


Symptoms can vary depending on the species of spider. Bites are most common on the face, mouth and paws. You may notice small puncture marks initially, however, once swelling occurs, these will be less apparent. Symptoms may take several hours to appear.


Nonvenomous spider bites may swell and become painful, however, unless your cat is anaphylactic, symptoms are usually self-limiting.


If you suspect your cat has been bitten by a venomous spider, keep him as still as possible to avoid the venom travelling more quickly through the system. Wash the bite wound carefully with soap and water and then transport him to a veterinarian. Try to keep the affected area below the heart if possible.

The brown recluse spider causes lesions which ulcerate and turn black over time.

Bites from widow spiders may cause the following symptoms:

  • Shivering
  • Intense pain
  • Drooling
  • Ataxia (wobbly gait)
  • Fever
  • Laboured breathing
  • Muscle weakness
  • Paralysis
  • Shock

In some cases, your cat may develop an anaphylactic reaction to a spider bite. This is a severe and life-threatening allergic reaction.

Symptoms of anaphylaxis include difficulty breathing, pale gums, swelling, vomiting, and diarrhea, trembling and collapse. Anaphylaxis is a medical emergency and requires urgent veterinary attention.


Treatment depends on the severity of the bite if it was a venomous spider or not. if you are at all unsure if the spider was venomous or non-venomous, take him to the vet, it is always better to err on the side of caution.

  • Nonvenomous spider bites are usually self-limiting. Wash the wound with antiseptic and apply ice to the area for 20 minutes. Monitor your cat for signs of infection.
  • Antivenom to treat venomous spider bites, these products contain antibodies which block the effect of venom.
  • Administration of painkillers.
  • Once your cat is home he will be prescribed muscle relaxants.
  • Removal of necrotic tissue if your cat has been bitten by a Brown recluse spider. It can take several months for ulcers to heal and will require management from the pet owner such as cleaning the area and changing bandages. Pain medications and antibiotics will also be given to control pain and treat bacterial infection.

Julia Wilson is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. She enjoys photography, gardening and running in her spare time. Full author bio Contact Julia

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