Nile monitor

Nile monitors eat lots of different animals.

They crack open snail shells.

They even eat crocodile eggs!

Nile monitors eat almost any animal they can overpower: frogs, toads, fish, rodents, lizards, small turtles, birds and their eggs, insects, spiders, crabs, worms and snails. Grown-ups have blunt back teeth and a sturdy skull for crushing the hard shells of snails and other mollusks.

They also eat crocodile eggs and raid turtle nests. Sometimes two monitors may work together at a crocodile nest: one distracts the mother crocodile while the other grabs eggs.

The IUCN describes a predator of most animals it can overpower, vertebrate and invertebrate, including crocodile eggs and freshwater turtle nests; in southern Africa adults eat many freshwater crabs while juveniles take frogs and invertebrates, and in the dry season up to half the diet can be carrion (Lenz 2004). The Animal Diversity Web lists frogs, toads, rodents, fish, lizards, small turtles, birds and eggs, insects, crabs, spiders, millipedes, earthworms and slugs, notes reports of pairs raiding crocodile nests, and describes hard-shelled mollusks, especially land snails of the genus Achatina, as a major food: adults have a deep skull, blunt crushing back teeth and a bowed lower jaw, which juveniles lack, probably reflecting a shift from insects to mollusks.

Nile monitors swim very well.

They climb trees and rocks.

They lie in the sun to warm up.

Nile monitors are strong swimmers and good climbers. They usually live alone, and when they are resting they bask on logs, rocks, trees or plants by the water. Young ones often lie on branches over the water and drop in if something disturbs them.

Nile monitors are wary. If one is approached, it usually runs away or jumps into the water. If it is cornered, it puffs up its body, hisses loudly and lashes its tail to warn the enemy away, so it is best to leave them alone.

The IUCN describes an adult that is largely terrestrial but climbs trees and rocks and swims strongly and actively, basking on waterside vegetation, trees, logs or rocks when inactive; in parts of the range it may aestivate in the dry season (Trape et al. 2012). The Animal Diversity Web adds that it is usually solitary and wary, walks with its body held well off the ground while flicking its tongue, hibernates in rock cracks or burrows in the colder parts of South Africa, and, when cornered, arches its back, inflates its body, hisses and lashes its tail, which can give a painful blow, before biting and releasing a foul-smelling musk as a last resort.

There are still many Nile monitors.

But people catch many for their skins.

Some are sold as pets.

The Nile monitor is listed as least concern: it lives across a huge area and is still common in many places. But in parts of Africa it is hunted heavily for its skin, which is made into leather, and for its meat, and many are sold as pets around the world. It is less common where it is hunted and is declining in Egypt's Nile Valley below Aswan.

International trade in Nile monitors is controlled by CITES. New dams in East Africa have even given it more places to live.

Wilms, Wagner, Luiselli, Branch, Penner, Baha El Din, Beraduccii, Msuya, Howell and Ngalason assessed Varanus niloticus as Least Concern (Global; assessed 21 October 2019, published 2021; trend stable) for its wide range, presumed large population and unlikely rapid decline. It is naturally very common but scarcer where hunted for meat (Trape et al. 2012); common at Lake Nasser but declining in the Nile Valley below Aswan.

In parts of Africa it is heavily exploited for leather; between 2010 and 2018, 369,210 wild-sourced skins and 48,958 live animals were traded internationally (CITES trade database, via IUCN). Young animals are offered to tourists, and in Egypt it is threatened by the pet trade, water pollution and some persecution. It is listed on CITES Appendix II, occurs in many protected areas, and thrives in reservoirs created by dams in East Africa.