The Nile monitor (Varanus niloticus) is a hefty reptile, also known as the water monitor, and Africa’s longest lizard, sometimes reaching lengths of over 2 metres – of which more than half is tail.
Seldom wandering far from water, it is a common sight across much of the region, usually seen rummaging around the riverine undergrowth, basking on a rock or swimming through the shallows. A versatile predator, able to swim, run and climb with equal ease, it will take prey from insects to small mammals, using its forked, flicking tongue to track down its quarry by scent.
- A Nile monitor’s tail may grow more than a metre in length. It serves as a counterweight when running, an oar to help power it through the water and a whip with which to lash out at an assailant in self-defence.
- Water monitors will ransack an unattended crocodile nest for its eggs. They are even said to work together, one provoking a female crocodile away from its clutch while another nips in to steal the prize.
- The biggest enemy of the Nile monitor is the martial eagle, which is capable of capturing and carrying away an individual weighing up to 4kg.
- In spring, a female Nile monitor breaks into a live termite mound to lay up to 60 eggs (the largest clutch size of any lizard) The termites repair the damage, leaving the eggs to incubate in warm, humid conditions. They hatch with the following spring rains, when the softened soil allows the hatchlings to break out.
- Nile monitors have been living wild in Florida, USA, since at least 1990. Having escaped from private collections, the reptile has adapted well to the subtropical wetlands and has become a menace to some native wildlife, including alligators. The majority of the established breeding population is in Lee County.