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
Arizona night lizard Arizona night lizard The Arizona night lizard ("Xantusia arizonae") is a species of small smooth-skinned gray-brown lizards with dark spots that sometimes form partial lines down the back. The lizard has a slightly flattened head. The scales of the underside and tail are larger than those of the upper side. The lizard grows to a length of 6 to 10 cm. Despite its name, the Arizona night lizard is primarily active during the day. The lizard's range extends across west-central Arizona. It is usually found in rock crevices or under plant debris. Its diet consists of insects and spiders. The