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
Philippine sailfin lizard Philippine sailfin lizard The Philippine sailfin lizard, crested lizard, sail-fin lizard, sailfin water lizard, soa-soa water lizard (Hydrosaurus pustulatus) or its native name "ibid" is an oviparous lizard living only in the Philippines. The Philippine sailfin lizard is an excellent swimmer and has flattened toes that enable it to run across water, similar to the basilisks. It is omnivorous, feeding on fruit, leaves, flowers, insects, and small animals . Males have a larger crest on their back than the females. The males also show a violet color as they grow older. Females are less colorful. The adults may reach up