Over 70, see text.
Monitor lizards, also known as biawak or goannas, genus Varanus, are members of the family Varanidae. They are, as the name says, lizards. They have a distinctive upper set of teeth to intimidate their predators when in danger. Varanus is a group of largely carnivorous lizards which includes the largest living lizard, the Komodo dragon, and the crocodile monitor. The closest living relatives are the anguid and helodermatid lizards.
Monitor lizards are usually large reptiles, although some can be as small as 12 centimeters in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semi-aquatic monitors are also known.