Pit Viper Snakebite Poisoning (Crotalid Envenomation) in Cats

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4 min read

Key takeaways

Pit viper bites are venomous bites from snakes of the crotalid family. 

  • Crotalids include rattlesnakes, copperheads, and cottonmouths (water moccasins)
  • All known or suspected snake bites in cats require emergency veterinary attention
  • Symptoms of venomous pit viper bites include swelling, discoloration, and sloughing of skin around the bite mark
  • In severe cases, small dots (petechiae) appear on the lips, gums, and tongue, and spontaneous bleeding and muscle tremors develop
  • Diagnostic tools include physical examination, bloodwork, and blood clotting tests
  • Treatment is antivenom alongside supportive care such as IV fluids, pain killers, and oxygen therapy
  • Prognosis depends on location of the bite, the type of snake involved, how much venom was injected, and how quickly treatment began after the encounter
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A closer look: Pit Viper Snakebite Poisoning (Crotalid Envenomation) in Cats

**Cats that are bitten or are suspected of having been bitten by a snake require emergency veterinary attention.**If possible, keeping the cat calm and still is recommended. At-home first aid attempts are unlikely to slow the onset of symptoms, so immediate transportation to a veterinarian is recommended.

Not all pit viper bites deliver venom. Pit vipers release venom voluntarily, and in many cases where they are striking as a defense, they do not release venom. Even so, emergency care is required as envenomation should always be assumed to create the best chance of survival.

Risk factors

Cats who spend time outside, particularly those that live in areas where snakes are found, are at higher risk. Overall, pit viper bites are rare in cats. Pit vipers are found all over North America.

The severity of envenomation depends on where on the body the cat was bitten, which species of snake was involved, the amount of venom injected, and the length of time before treatment begins.

Cats with bites to their head or limbs are more likely to survive than cats with bites to the thorax or abdomen. Larger cats are more likely to survive than smaller cats.

Cats bitten by pit vipers whose venom is neurotoxic have a harder time recovering. This includes the mojave rattlesnake, timber rattlesnake, and canebrake rattlesnake.

Possible causes

Pit vipers are snakes from the crotalid family. This family includes:

  • Rattlesnakes
  • Cottonmouths (also known as water moccasins)
  • Copperheads

When pit vipers strike defensively, they choose whether to deliver venom or not, and how much. In many cases, a bitten cat is not injected with venom (envenomated).

Although many bites deliver no venom, the consequences of venom injection are severe enough that any cat bitten by a snake requires veterinary examination immediately.

Main symptoms

Testing and diagnosis

If the encounter with a snake is witnessed, diagnosis is self evident. In cases where a snake bite is suspected, diagnostic tools include:

  • Physical examination
  • Bloodwork
  • Blood clotting profiles
  • Urinalysis
  • Electrocardiogram

Steps to Recovery

Treatment is antivenom (also known as antivenin). Supportive therapies include:

  • IV fluids
  • Oxygen therapy
  • Pain medication
  • Wound care to manage sloughing skin

In some cases, antibiotics are administered to prevent infection at the wound site.

Ongoing monitoring for a period of between 12 and 24 hours is required. Repeated tests are used to monitor for organ damage or other side effects. These tests include:

  • Monitoring of tissue damage by marking the leading edge of tissue damage
  • Repeated blood clotting profiles

With rapid treatment, the prognosis is fair. Symptoms may last several days before resolving. In cases where the cat has been bitten in the thorax or abdomen, when a lot of venom was injected, when the cat is in poor health, or when treatment is delayed, the prognosis is guarded. Left untreated, pit viper bites are potentially fatal.


Prevention requires cats to be kept away from environments where snakes are common. Indoor cats are at very low risk of snake bites.

Is Pit Viper Snakebite Poisoning (Crotalid Envenomation) in Cats common?

Pit viper bites are rare in cats, but more common in outdoor cats in areas where pit vipers are common.

Typical Treatment

  • Antivenom
  • Supportive care


Sharon M. Gwaltney-Brant , - Writing for Merck Veterinary Manual
Laurie Anne Walden - Writing for dvm360®
Lyndi L. Gilliam, Jill Brunker - Writing for Veterinary Clinics: Small Animal Practice

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