Mexican beaded lizard Mexican beaded lizard The Mexican beaded lizard ("Heloderma horridum") is a species of lizard in the family Helodermatidae, one of the two species of venomous beaded lizards found principally in Mexico and southern Guatemala. It and its congener (member of the same genus) the Gila monster ("Heloderma suspectum") are the only lizards known to have evolved an overt venom delivery system. The Mexican beaded lizard is larger than the Gila monster, with duller coloration, black with yellowish bands. As it is a specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of
Mexican beaded lizard desert, tropical deciduous forests and thorn scrub forests, but are found in pine-oak forests, with elevations from sea level to 1500 m. In the wild, the lizards are only active from April to mid-November, spending about an hour per day above the ground. The Mexican beaded lizard "H. horridum" is found in Mexico, from Sonora to Oaxaca. The Rio Fuerte beaded lizard ("H. exasperatum") is found from southern Sonora to northern Sinaloa. The Chiapan beaded lizard ("H. alvarezi") is found in the northern Chiapas and the depression of the Río Lagartero in Huehuetenango to northwestern Guatemala. The ranges of these