Monitor (lizard) - biology.

Monitor (lizard) - biology. Monitor (lizard), or goannas, common name for a genus of lizards that includes the largest living lizard, the Komodo dragon. Monitors live in tropical and desert areas throughout Africa, in Asia from Arabia through southern China and Malaysia, and in the East Indies and Australia. There are about 30 species in the genus, ranging from 20 cm to more than 3 m (8 in to 10 ft) long. They are characterized by a long, forked, snakelike tongue, and are able to engulf and swallow large prey whole. They are sleek, fast runners with tapered heads, long necks, strong legs, and long, powerful tails. Monitors feed on insects, birds, reptiles and their eggs, small mammals, and carrion. Monitors are among the oldest living lizards. They are related to the mosasaur, a marine lizard that lived from 136 million to 65 million years ago and ranged up to 10 m (33 ft) long. The largest monitor is the 165-kg (365-lb) Komodo dragon. It lives on several islands, including Komodo, in Indonesia. This lizard is a fierce predator and scavenger; its mouth carries a virulent bacteria, and its bite alone can be fatal. Recent studies have shown that monitors also have venom-secreting glands in their mouths and can produce low levels of venom to help subdue prey. Although monitors are mainly terrestrial, some species also climb trees and are good swimmers. The large water monitor of East India can swim far from land. Two species, the Komodo dragon and the Gray's monitor, are listed on the World Conservation Union (also known as IUCN) Red List of Threatened Species. Scientific classification: Monitors make up the genus Varanus and the family Varanidae. The Komodo dragon is classified as Varanus komodoensis, the water monitor as Varanus salvator, and the Gray's monitor as Varanus olivaceus. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.