Fearsome in appearance and deliberate in movement, the Gila monster and its Mexican cousin, the beaded lizard, are the only lizards that are poisonous. These docile, slow-moving creatures are unlikely to bite pets or people, and their venom delivery system is not as efficient as that of a snake. But once one of these lizards clamps on, prying it off can be very difficult. The longer he hangs on, the more venom will be injected into the victim. Venom is injected from glands within the lower jaw.

The Gila monster is found in the desert regions of Arizona, western New Mexico, southeastern California and the southern tip of Nevada, the extreme southwest region of Utah and northwestern Mexico. The beaded lizard is only found in Mexico.

The best way to avoid a bite from a poisonous lizard is to keep your pets from roaming. Because these species are found in desert conditions, it's unlikely your pet will encounter one, unless he's lost in the desert.

Gila and beaded lizards are protected species. People who handle and house them should be properly trained. Indeed, the few bites reported each year are mostly from people who keep and handle captive specimens for research.

What to Look For

Watch for bleeding, swelling and extreme pain at the bite site. Other symptoms include:

Hypotension (low blood pressure)

Excessive salivation

Tearing from the eyes

Frequent urination

Defecation

Inability to vocalize

Veterinary Care

Your veterinarian will conduct a physical examination, and may include electrocardiograms to detect arrhythmias and blood pressure readings to detect hypotension. However, the only definitive way to diagnose lizard venom toxicity is by actually witnessing the lizard biting the victim.

Treatment includes removing the lizard if still attached to your pet. This can be done by either placing a flame under the lizard's jaw or prying open the mouth. Your veterinarian will flush and soak the bite wound, monitor and treat hypotension and/or arrhythmias and administer antibiotics to ward off infection.