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Why Did the Monitor Lizard Become Endangered?

There are more than 50 species of monitor lizards, all of which are members of the genus Varanus. Most monitors are carnivores at the top of the food chain, which makes them highly susceptible to environmental pollutants and toxins that cause illnesses and genetic mutations. Though not all monitor lizards are endangered, they are all threatened by environmental degradation, human encroachment, pollution and other factors. Numerous species of monitors are critically endangered, including the Komodo dragon, the Bengal monitor and the yellow monitor. In some countries, catching or killing any monitor is illegal because the genus is protected by local endangered species acts.

Food Chain Toxicity
- The overwhelming majority of monitor lizards are carnivores. Animals at the top of the food chain are particularly vulnerable to environmental toxins. This is because, as nutrients cycle up the food chain, fewer useful calories become available to animals. The toxicity of chemical pollutants, however, is not weakened and because there are fewer calories to buffer this toxicity, predators are especially vulnerable. Monitors that eat amphibians, insects and mammals that have been exposed to environmental pollutants may suffer from genetic mutations, lowering the survival of the species. They may also be poisoned by food ingested by their prey.
Habitat Destruction
- Habitat destruction has contributed to the endangerment or extinction of thousands of species. Monitor lizards are especially vulnerable to the consequences of habitat destruction because of their large size. They require substantial territory to mate, eat and engage in species-typical behaviors. Human encroachment in the form of cutting down trees, building houses, construction of commercial districts and other behaviors that limit monitors' territory has dramatically reduced their populations in the wild.
Hunting
- Monitors have thick, leathery skin that has been used for centuries to make human luxuries. The Komodo dragon was hunted nearly to extinction because its skin was so desirable. In some areas of the world, monitor lizard meat is considered a delicacy. This has resulted in excessive hunting of some species of monitors, which has driven them to the brink of extinction.
Pet Trade
- Exotic pets have been increasing in popularity since the 1990s. Monitors are highly valued commodities in the pet trade because they are generally docile, trainable and have long lifespans. The high demand for these pets, however, has resulted in a very profitable illegal pet trade. Because most pet owners are not equipped to meet the needs of these sensitive animals, hundreds die in captivity every year. Their numbers in the wild have been dramatically reduced due to the pet trade.

Animals & Science