Savannah Monitor

In the wild, mostly bugs. Studies of the stomach contents of wild savannah monitors find a diet dominated by invertebrates, particularly millipedes, which can make up the bulk of it, along with beetles, grasshoppers, crickets, snails, and scorpions. Larger prey such as eggs, small mammals, other reptiles, and carrion is taken opportunistically but is a minor part of the picture. This matters because in captivity the species is very often fed a diet of mice and rats, which is far too rich in fat and protein for an animal built to process insects, and the result is obesity, fatty liver disease, and gout, which kill most captive savannah monitors young.

Because they are sold cheaply and their needs are widely misunderstood. Most are wild-caught hatchlings imported in bulk from West Africa, often stressed, dehydrated, and carrying parasites on arrival. New keepers, following outdated advice, then house them in enclosures far too small for an animal that reaches a metre or more, keep them too cool and too dry, feed them rodents instead of insects, and handle them too much. A savannah monitor kept correctly, in a large, deep, warm enclosure with a thick substrate to dig in, a proper basking temperature, and an insect-based diet, is a hardy, long-lived, intelligent pet, but that setup is a serious commitment that the low purchase price disguises.

Not seriously, but they command respect. A large savannah monitor has strong jaws with crushing teeth, sharp claws, and a heavy tail it can swing hard, and a defensive bite can cause a deep, ragged wound that is prone to infection from mouth bacteria. Monitors do have oral venom glands, an ancestral feature of the group, but in the savannah monitor they are poorly developed and the venom plays little or no role; the injury from a bite is mechanical. A wild savannah monitor will usually flee or bluff rather than attack, and a well-socialised captive one rarely bites at all.

All three are in the genus Varanus, but they occupy different sizes and lifestyles. The savannah monitor is a medium, stocky, terrestrial African species specialised on hard-bodied invertebrates in a strongly seasonal grassland. The Asian water monitor is a large, semi-aquatic Southeast Asian generalist, one of the biggest lizards in the world, common even in cities. The Komodo dragon is the giant of the family, restricted to a few Indonesian islands, a true apex predator of large mammals with a well-developed venom. The savannah monitor is the smallest and least dangerous of the three and the one most often kept as a pet.