Monitor Lizard

Genus Varanus

Reptile

Transcript:

Today on Animal Fact Files we’re talking about monitor lizards. These are some of the largest living lizards in the world. Nearly half of the monitor lizard species alive today are found in Australia - though there they’re referred to as goannas! Sometimes Australian skinks are misidentified as goannas, but true goannas are from the monitor lizard genus. Apart from Australia, these large lizards are also found in Asia, Africa, and Oceania. Monitor lizards aren’t native to the western hemisphere, however they can be found there as invasive species. Typically the monitor lizards found living in non-native habitats, like the Americas, were released by pet owners or are the offspring of monitor lizards released by pet owners. There are nearly seventy living and classified monitor lizard species. Some, like the short tailed monitor, don’t quite live up to their title as the largest living lizards and only reach just over seven inches (17.8cm) in length; but the largest living monitor lizards, and in fact the largest living lizards in the world, are the komodo dragons who can be nearly ten feet (3m) long!

These lizards are adaptable. Monitor lizards live in a variety of habitats including dense forests, mangrove swamps, arid savannahs, and deserts, though usually their species plays a role in their preferred habitats. Some monitor lizard species are aquatic or semi aquatic, meaning they spend an average amount of their time in water; others are terrestrial and thus tend to stay with their feet on the ground; and others are semi arboreal to fully arboreal, meaning they may spend some to nearly all of their time in trees!

Monitor lizards are closely related to snakes and beaded lizards, like the gila monster, so it shouldn't be surprising that monitor lizards produce their own venom. It was once believed that the only venomous lizards were the beaded lizards, with monitor lizards having toxic bites thanks to bacteria filled mouths, but now it’s known monitor lizards also come with a venomous bite! Since monitor lizards tend to be top predators, it’s believed that they use their venom to help subdue prey or even digest their food, but more research needs to be performed before this can be concluded with more certainty.

Threats to monitor lizards include habitat destruction and hunting. These lizards may be used for meat or their skin may be used to make leather; however, their relationship with humans isn’t all bad because they enjoy the food scraps left in human garbage! Monitor lizards can be described as scavengers and will take meals opportunistically. In the wild, these lizards eat other lizards, snakes, frogs, fish, birds and their eggs, mammals like deer and pigs, arthropods, molluscs, carrion, and even fruit! Monitor lizards can use their forked tongues to “smell” the air like snakes. In doing this, monitor lizards can determine where something is based on the amount of scent particles of each fork of their tongues. Pretty ingenious, right? Actually, monitor lizards are believed to be some of the smartest living lizards! In captivity, they've been taught to open hinged doors that lead to food and to wait patiently on scales in order to be accurately weighed.

The name “monitor” may be in reference to them warning - or monitoring - for signs of crocodiles. People would use these lizards as an alarm system for indicating the presence of crocodiles in an area. The name “monitor” may also stem from these lizards’ ability to stand on their rear legs to monitor their surroundings. Monitor lizards are generally diurnal animals. They typically breed during warm, dry months with their eggs being laid shortly after. Monitor lizards lay their eggs in nests and incubation takes 90 to 270 days depending on the species. Hatching times for monitor lizard babies often correspond with the wet season and/or prey abundance. Like all living reptiles, even aquatic monitor lizards have to lay their eggs on land. These animals are considered long lived and may live decades.

For more facts on monitor lizards check out the links in the description. Thank you to Joey as well as Andrew, Gregory, Charlie, and Jason for today’s requests! Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.