Komodo dragons are the largest, heaviest lizards in the world — and one of the few with a venomous bite. These stealthy, powerful hunters rely on their sense of smell to detect food, using their long, forked tongues to sample the air. They can spend hours waiting for a sizable meal to wander within range before launching a deadly attack with their large, curved and serrated teeth.
Most of the “dragon’s” attempts at bringing down prey are unsuccessful. However, if it is able to bite its prey, bacteria and venom in its saliva will kill the prey within a few days. After the animal dies, which can take up to four days, the Komodo uses its powerful sense of smell to locate the body. A kill is often shared between many Komodo dragons.
These lizards can see objects as far away as 985 feet (300 meters), so vision does play a role in hunting, especially as their eyes are better at picking up movement than at discerning stationary objects. However, they are thought to possibly have terrible night vision. (source-learn more)