- Common Name
- Mexican beaded lizard, beaded lizard
- Genus Species
- Heloderma (studded skin) horridum (rough or horrible) exaspertatum (rough)
- The stripes and spots (white to yellow in color) on its black bumpy skin give this lizard a beaded appearance and its name. It has a thick, fleshy tail that is slightly shorter than the rest of the body, and short powerful limbs.
- 32.5-45 cm (13-18 in.) adult average length
- 2.3-2.7 kg (5-6 lbs.) adult average
- Primarily consists of eggs, young birds, mammals, and reptiles
- 28-30 days; young are able to survive without parental support
- Sexual Maturity
- 2-3 years
- Life Span
- In excess of 30 years
- Southwestern United States; northern and southwestern Mexico to northern Guatemala
- The lizard inhabits desert scrub and tropical thorn woodlands. Beaded lizards spend as much as 98% of their lives underground.
- Global: No data
- IUCN: Vulnerable
CITES: Appendix II
USFWS: Not listed
- The Mexican beaded lizard and its close relative, the gila monster (Heloderma suspectum), are the only two venomous lizards in the world. They possess venom glands in their lower jaws. The venom is delivered by capillary action along grooved teeth. In essence, they chew the venom into their prey. There is no anti-venom for the beaded lizard bite.
- While they are at home in the desert, beaded lizards actually need a higher humidity than other desert reptiles.
- Although beaded lizards appear sluggish, they are able to move rapidly when provoked. They can also produce a hissing sound to warn off intruders.
- When food is scarce, the lizard metabolizes fat stored in its tail.
Ecology and Conservation
Beaded lizards play a pivotal role in the desert ecology of the American southwest. By feeding on the eggs or young of small desert inhabitants, beaded lizards help control their populations. As with any small carnivore, venomous or not, they are preyed on extensively by larger predators.
Gotch, A.F. Reptiles, Their Latin Names Explained. New York: Blandford Press, 1986.
Mattison, Chris. Lizards of the World. New York: Facts on File, Inc., 1989.
Rogner, Manfred. Lizards. Vol. 2. Malabar, Florida: Krieger Publishing Co., 1994.