Lizard, Gray’s Monitor (Butaan)

Gray's Monitor, L.A. Zoo (Photo by Charlie Morley)

Scientific Name: Varanus olivaceus

Until its rediscovery in the 1980s, the Gray’s monitor was believed to be extinct.

Little is known about this reclusive reptile; one of the largest lizards in Asia.

A Very Big Family

Monitor lizards are classified together under the family Varanidae and the genus Varanus. The genus Varanus contains over 56 different species of lizards, ranging in size from the eight-inch pygmy monitors from Australia to the nine and one half foot long Komodo dragon. Some are smaller than a foot, but the Komodo dragon can grow to over 200 pounds. Despite this vast difference in size, monitor lizards have many similarities. All monitors are carnivorous and are often aggressive, hunting and eating anything they can find. Unlike other lizards, monitors cannot detach and grow back their tails. Instead, they use them as a defensive weapon, striking out at enemies with a quick, stinging lash. Most monitors, including the Gray’s, are tropical animals, and are comfortable in water, on land, and within the trees of forests and rainforests.

This monitor is classified as vulnerable by the International Union for Conservation of Nature (IUCN), due to habitat loss and predation by man.

The Gray’s monitor (or “Butaan,” as it is called by the locals) can be found on only a few of the islands in the Philippines, primarily on Luzon and Polillo. It spends most of its time in the trees of the rainforests.

The Gray’s monitor is part of a small group of Asian monitors that eat fruit as the main part of their diet. As a juvenile it eats snails, crabs, and insects, continuing to do so into adulthood as a supplement to fruit.

The Gray’s monitor is one of the largest lizards in Asia, growing up to five feet in length from the tip of its snout to the end of its tail and weighing up to 20 lbs. It is olive green in color, which provides the cryptic coloration it needs to blend into its surroundings and avoid detection. Its feet have five long, well-developed claws that help it climb and grab the fruit it eats. Its teeth, unlike other monitor lizards, are blunt, which helps them pick fruit and crush snails.

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