Beaded lizard

The Mexican beaded lizard (Heloderma horridum) is the most famous of the four species of venomous beaded lizards found principally in Mexico and southern Guatemala. It and its congener the Gila monster (Heloderma suspectum) are the only lizards known to have evolved an overt venom delivery system. The beaded lizard is larger than the Gila monster, but has duller coloration, black with yellowish bands of differing width depending on the species. As it is a specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of debate among scientists. However, this venom has been found to contain several enzymes useful for manufacturing drugs in the treatment of diabetes, and research on the pharmacological use of its venom is ongoing.