Komodo dragons have thrived in the harsh climate of Indonesia's Lesser Sunda Islands for millions of years. They prefer the islands' tropical forests but can be found anywhere, even sometimes swimming between islands.

Reaching up to 10 feet in length and more than 300 pounds, Komodo dragons are the heaviest lizards on Earth.

It used to be believed that these lizards had various strains of bacteria in their saliva that killed prey, but this theory has been discredited. In 2009, MRI scans of a preserved skull showed the presence of two glands in the lower jaw. Researchers extracted one of these glands from the head of a terminally ill dragon in the Singapore Zoological Gardens, and found it secreted several toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey.

They have 60 razor sharp teeth up to one inch (2.5 cm) long. Lost or damaged teeth are constantly replaced, and they can go through four or five sets of teeth in their lifetime.

Not only are Komodo dragons big, but they have an appetite to match. When these massive lizards sit down to a meal, they're capable of swallowing as much as 80% of their own bodyweight in food. With such large meals, dragons can survive on as few as 12 meals a year.

As with most reptiles, dragons use their forked tongues instead of noses to smell. They are able to locate a dead or dying animal from a range of up to 6 miles (10 km).

After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting it does not relish the scent of its own excretions.

Komodo dragon skin is reinforced by armored scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. The only areas lacking osteoderms on the head of the adult Komodo dragon are around the eyes, nostrils, mouth margins, and pineal eye, a light-sensing organ on the top of the head.

Young dragons are vulnerable to cannibalism by adults, which get approximately 10 percent of their diet from consuming juveniles of their own species. As a result, juveniles spend the beginning of their lives living in trees. Their claws make them ideal climbers, but only when young--they become too heavy to climb trees as adults.

In an all-out sprint, a Komodo dragon can run at an impressive 12 miles per hour (19 kph).