Any of about 30 species of 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 {{link=Komodo dragon">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.