Lizard heads called the parietal eye, a basal ("primitive") feature also present in the tuatara. This "eye" has only a rudimentary retina and lens and cannot form images, but is sensitive to changes in light and dark and can detect movement. This helps them detect predators stalking it from above. Until 2006 it was thought that among lizards, only the Gila monster and the Mexican beaded lizard were venomous. However, several species of monitor lizards, including the Komodo dragon, produce powerful venom in their oral glands. Lace monitor venom, for instance, causes swift loss of consciousness and extensive bleeding through its
Southern alligator lizard Southern alligator lizard The southern alligator lizard ("Elgaria multicarinata") is a common species of lizard native to the Pacific coast of North America. It ranges from Baja California to the state of Washington and lives in a variety of habitats including grasslands, chaparral, forests, and even urban areas. In dry climates, it is likely to be found in moist areas or near streams. The generic name "Elgaria" is possibly named for an "Elgar" or a pun on "alligator." The specific name "multicarinata" refers to the keeled scales characteristic of this species. The common name "alligator lizard" is a reference to