The Komodo dragon is the largest living lizard. Adults weigh 70 to 136 kilograms (154 to 300 pounds), and they are 1.8 to 3 meters (6 to 10 feet) long. Males are heavier and longer than females. Its group, the monitor lizards, has ancestors from more than 100 million years ago, but scientists did not formally record the Komodo dragon as a new species until 1910.

A Komodo dragon finds food mainly by its sense of smell. It can smell dead animals up to 4 kilometers (2.5 miles) away. It uses its long, forked tongue to sample the air, then touches the tongue tip to the roof of its mouth, where Jacobson's organs analyze chemicals in the air. If more scent molecules are on the left tip of its tongue than the right, it knows food is on its left.

The head matters too. A Komodo dragon walks with its head swinging side to side, which helps it sense the direction of food. Its eyes are better at picking up movement than at noticing things that are still, and its retinas have only cones. It can see things as far as 300 meters away, but its hearing range is smaller than a person's.

A Komodo dragon is not built for long chases. It can run in short bursts of 16 to 20 kilometers per hour (10 to 13 miles per hour). It waits quietly in one spot for food to come by, and it eats deer as well as dead animals that it finds. It can walk up to seven miles in a day, and its home range can be as large as 1.9 square kilometers.

A Komodo dragon eats very quickly, and it has been seen eating 5.5 pounds of meat in one minute. Movable joints let its lower jaw open unusually wide, and its stomach expands easily. It has about 60 short, serrated teeth, and goes through four or five sets in a lifetime. When food is found, the largest males eat first, then smaller males and females, then young ones.

A Komodo dragon is a good swimmer, and it has been seen swimming to nearby islands. It lives on a few islands in Indonesia, where it rests in burrows at night. Its young begin life in an egg, and then climb trees and live in them.

Words to know

• monitor: kind of lizard
• Jacobson's: scent organs
• molecules: tiny particles
• serrated: with tiny notches