Misconceptions often surround whether lizards are venomous. While most lizards are not venomous, a few possess specialized venom delivery systems. Understanding the distinction between venomous and poisonous animals, and identifying venomous species, clarifies this topic. This article explores lizard bites and highlights species warranting caution.
Understanding Lizard Bites
To clarify lizard bites, distinguish between “venomous” and “poisonous.” A venomous animal actively injects toxins, typically through a bite or sting, using specialized structures like fangs. A poisonous animal delivers toxins passively, usually when ingested or absorbed through skin contact. Most lizard bites, while painful, do not involve toxin injection. Non-venomous bites can still cause lacerations or punctures and may carry a risk of bacterial infection.
The Few Venomous Lizards
Only two lizard species are recognized as venomous: the Gila monster (Heloderma suspectum) and the Mexican Beaded Lizard (Heloderma horridum). The Gila monster inhabits the southwestern United States (Arizona, Utah, Nevada, California, New Mexico) and Sonora, Mexico. The Mexican Beaded Lizard is found in Mexico and southern Guatemala. Both belong to the family Helodermatidae and share a unique venom delivery method.
Unlike snakes, these lizards have venom glands in their lower jaws that produce toxins. Their venom flows along grooves in their teeth, entering the wound as the lizard chews and maintains its grip. A Gila monster bite can be intensely painful, causing swelling, nausea, dizziness, and low blood pressure; fatalities are rare. The Mexican Beaded Lizard’s venom causes similar symptoms; human deaths are uncommon. These lizards typically bite defensively, usually after provocation.
Lizards Often Misunderstood
Many other lizard species are inaccurately perceived as venomous. Komodo dragons (Varanus komodoensis) are large monitor lizards known for powerful bites. While their saliva contains diverse bacteria and their venom includes anticoagulants, they lack the active venom delivery system of Gila monsters or Mexican beaded lizards. Their bites primarily cause tissue damage and bacterial infection.
Other monitor lizards also have strong jaws and sharp teeth, inflicting painful bites and significant bleeding. Research indicates many monitor lizards produce venom with anticoagulant properties, causing wounds to bleed more. However, this venom is generally not potent enough to be life-threatening; the main concern is physical trauma and bacterial infection.
Similarly, iguanas, though capable of painful bites with their sharp, serrated teeth, are not venomous. Their bites can cause deep lacerations and bacterial infection, including Salmonella, necessitating thorough wound cleaning and medical attention.
Responding to a Lizard Bite
If bitten by a lizard, the initial response depends on whether the species is venomous. For a suspected venomous bite (e.g., Gila monster or Mexican Beaded Lizard), immediate medical attention is necessary. Remove the lizard quickly, by prying its mouth open with a stick or immersing it in water, ensuring a solid foothold if prying.
Clean the wound thoroughly with soap and water, keeping the bitten area below heart level. Avoid applying ice, tourniquets, cutting the wound, or sucking out venom. Medical professionals will clean the wound, check for broken teeth fragments, and ensure current tetanus immunization. No specific antivenom exists for Gila monster or Mexican Beaded Lizard bites; treatment focuses on supportive care for symptoms like pain, swelling, and low blood pressure.
For non-venomous lizard bites, clean the wound thoroughly with soap and water. Apply antiseptic or antibiotic ointment and cover with a bandage. Monitor the wound for signs of infection: increased redness, swelling, pus, or fever. If infection signs develop, or if the bite is deep or causes significant pain, seek medical evaluation.