Scientific Name: Heloderma horridum
This lizard shares many characteristics with the more famous Gila monster, and it’s not surprising – they are the only two surviving members of an ancient group of lizards called the Monstersauria.
The Mexican beaded lizard, along with its relative the Gila monster, are the world’s only two venomous lizards. The animal needs to chew its victim in order to inject the poison, which is produced in its salivary glands and delivered through grooves in its teeth.
STATUS: The Mexican beaded lizard is listed as Least Concern by the International Union for Conservation of Nature (IUCN). Its habitat is being destroyed by human development.
HABITAT: The animals are found in the thorn scrub and deciduous forest of the western coast of Mexico and northern Guatemala. Mexican beaded lizards make their homes in abandoned mammal burrows, under rocks, or in tunnels they have dug. They frequently live near permanent water sources. Active primarily at dusk and after dark, beaded lizards escape the heat of the day by hiding in their homes.
DIET: These carnivores eat eggs, young birds, insects, lizards, snakes and rodents. Beaded lizards play a crucial role in desert ecology by helping to regulate the population of their prey. The lizards are able to metabolize fat stored in their tail when food is scarce.
PHYSICAL CHARACTERISTICS: Beaded lizards have cylindrical bodies with wide, flat heads and short, strong legs ending in feet with five clawed toes. The white to yellow stripes and spots on their black, bumpy skin create the impression of beads. The top of their bodies is covered with large, hard scales while the belly has soft scales. The lizard’s total length is about 30 to 35 inches, with the tail making up nearly half that length. Although Beaded Lizards appear sluggish, they can move quickly when threatened and make a hissing sound to discourage predators. The five- to six-pound lizard reaches sexual maturity in two to three years and can live more than 30 years. Their breeding season is in February and March and about two months later, females bury 3-13 elongated eggs about five inches deep. Young are hatched at about five months.
While a bite from a beaded lizard is not usually life-threatening to humans, the injury does require medical care. Fortunately, unprovoked attacks on humans are very rare. Most bites occur when a person tries to annoy or handle the animal. The lizards may also bite potential predators such as coyotes or raptors when threatened.