Watch Sadisflix. Monitor Lizards play a very important role in the food chain of Sri Lanka’s lagoons and forests, if they make it through the first year. Mature Monitor Lizards can grow up to 8 feet (2.4 meters) long, making some of them the largest reptiles on Earth. A mother’s role ends with the laying of eggs and hatchlings are left to fend for themselves, find food and keep to the relative safety of the trees.