Any of about 30 species of lizards (genus Varanus, family Varanidae), found in the Old World tropics and subtropics. Most have an elongated head and neck, a heavy body, a long tail, and well-developed legs. The smallest monitor grows to 8 in. (20 cm), but several species (e.g., the Komodo dragon) are very large. The two-banded, or water, monitor (V. salvator), of South Asia, grows to 9 ft (2.7 m). The perenty (V. giganteus), of Australia, grows to 8 ft (2.4 m). The so-called earless monitor (Lanthanotus borneensis), a rare lizard of Borneo and the only species of the family Lanthanotidae, grows to 16 in. (40 cm) long