Monitor lizards are a large species of lizards. Like other lizards, they are reptiles (class Reptilia). Monitor lizards come under the genus Varanus. In the genus Varanus, there are about 80 recognized species. The family Varanidae probably originated 65 million years ago in Asia. So, these reptiles are one of the oldest surviving inhabitants of the planet.
The name of the genera Varanus originated from the Arabic word “warallwaran”. It means “dragon” or “lizard beast”.
Our wildlife guide to the monitor lizard covers all the important details of this reptile. You can quickly get to the following sections for knowing about monitor lizards.
- Latin name (Genus): Varanus
- Family name: Varanidae
- Size: 2-3 meters
- Weight: 79-91 kilograms
Skip to: Characteristics, Range & habitat, Diet, Behaviour, Fun facts, Video
Monitor Lizard characteristics
Monitor lizards, one of the iconic reptiles living on the planet, have comparably long necks, strong tails, and claws. Their limbs are also well-built. An adult monitor lizard’s height ranges from 20 centimeters to over 3 meters. The Komodo monitor lizard or simply Komodo dragon is an apex predator over 3 meters in height.
Monitor lizards are generally terrestrial animals. However, some monitor lizard species are semiaquatic and arboreals. The monitor lizards are carnivorous animals.
Anatomical and molecular studies reveal that the monitor lizards and possibly all lizards are venomous partially. Monitor lizards’ venom is diverse and complex. The quality of the venom depends on the diverse ecological factors of their habitats. Monitor lizards like other reptiles lay eggs. That’s why they are called oviparous animals.
Range & habitat
Monitor lizards live mainly in the selected regions of Africa, Asia, and Oceania. Recently, monitor lizards have started to live in the Americas too.
Let’s look at the range of monitor lizards in detail. Monitor lizards cover a vast area of the following regions:
- Africa
- India
- China
- The Ryukyu Islands of southern Japan
- Southeast Asia: Thailand, Brunei, Indonesia, and the Philippines
- New Guinea
- Australia
- The islands of the Indian Ocean and the South China Seas
The West African Nile monitor lizard has started to live in South Florida and Singapore as an invasive species.
As it is mentioned earlier, monitor lizards are terrestrial, arboreal, and semiaquatic. So, they are found in lands, trees, and near the wetlands.
Diet
Some species of Monitor lizards are carnivores. They feed on a variety of insects, crustaceans, arachnids, mollusks, fish, amphibians, other small reptiles, birds, and mammals. Monitor lizards also eat eggs, fruits, and vegetation. The diet of a monitor lizard depends on where it lives. It adapts itself according to the natural resources available in the habitat.
The young monitor lizards eat invertebrates. When they become adults, they start to eat vertebrates. Some of the largest species of Monitor lizards, like the Komodo dragon prey on deers. Deers make up 50% of their diet. Three species living in the Philippines, which live in trees, mainly eat fruits.
Behavior & lifestyle
Monitor lizards are solitary animals. However, some species of monitor lizards are found in groups of 25 monitors.
The group of monitor lizards maintains a vast territory. They remain active throughout the day in their territory and prey on mammals and other small reptiles.
Monitor lizards lay 7-37 eggs. They cover the eggs with soil or hide the eggs in the hollow of tree stumps.
Let’s know more about the monitor lizard species that are native to Africa. These monitor lizards show some interesting behaviors. You can read about their behavior and lifestyle below.
Nile monitor (Varanus niloticus)
Nile monitors, a large member of the monitor lizard’s family, live in Sub-Saharan Africa and along the Nile. It is also called the African small-grain lizard and iguana.
Nile monitors are carnivores. These monitors are well-adapted for an aquatic lifestyle. They can climb trees and quickly run on land.
West African Nile monitor (Varnus stellatus)
West African Nile monitors are native to West African forests and nearby areas of the savannah region. Recently these monitors have been introduced to South Florida, United States as an invasive species.
Previously ornate monitors were included in the Nile monitor species. However, the Nile monitors and West African Nile monitors show similar behavior and lifestyle.
Ornate monitor (Varanus ornatus)
Ornate monitors live in West and Middle Africa. This monitor is large and they can grow close to 2 meters in length.
It was also considered as one of the subspecies of the Nile monitor until 1997. The recent studies have cleared all the doubts about this “species complex”. Ornate monitors are mostly found in the canopy forests.
Fun monitor lizard facts
Here is a list of “Top 5 Fun Monitor Lizard Facts” which is definitely astonishing. Let’s know some interesting facts about the monitor lizards below.
- Megalania (Varanus priscus), an extinct monitor lizard species, can grow up to 7 meters or 23 feet!
- Monitor lizards have the highest standard metabolic rate of all the reptiles living on the earth.
- Monitor lizards are intelligent animals. Some of the species can count numbers. Studies show that Varanus albigularis, a monitor lizard species, can differentiate numbers up to six!
- Nile monitors show an interesting preying technique. One monitor lures the female crocodile out of her nest. The other monitors eat the eggs. The previous one also joins the feast later.
- Komodo dragons can recognize their keepers and each monitor has some distinct personalities.
Meet the monitor lizard
Did you enjoy learning more about the monitor lizard? Have you ever met this unique creature face-to-face? Tell us about your monitor lizard experience in the comment section below. Because those who care share!
References
- “Ackie Monitor Care Sheet“. Reptile Range. Retrieved 8 April 2020.
- Bauer, Aaron M. (1998). Cogger, H.G.; Zweifel, R.G. (eds.). Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 157–159. ISBN 0-12-178560-2.
- Ed Yong, “Florida’s Dragon Problem”, The Atlantic April 20, 2016
- Pianka, Eric R.; King, Dennis R; King, Ruth Allen (2004). Varanoid Lizards of the World. Bloomington, Indiana: Indiana University Press.
- Auffenberg, Walter (1981). The Behavioral Ecology of the Komodo Monitor. University Press of Florida.
- Greene, Harry W. (1986). Diet and Arboreality in the Emerald Monitor, Varanus Prasinus, with Comments on the Study of Adaptation. Chicago: Field Museum of Natural History. OCLC 14915452. OL 7155983M.
- Welton, L. J.; Siler, C. D.; Bennett, D.; Diesmos, A.; Duya, M. R.; Dugay, R.; Rico, E. L. B.; Van Weerd, M.; Brown, R. M. (2010). “A spectacular new Philippine monitor lizard reveals a hidden biogeographic boundary and a novel flagship species for conservation“. Biology Letters. 6 (5): 654–658. doi:10.1098/rsbl.2010.0119. PMC 2936141. PMID 20375042.
- Struck, U; Altenbach, AV; Gaulke, M; F, Glaw (2002). “Tracing the diet of the monitor lizard Varanus mabitang by stable isotope analyses (d15N, d13C)”. Naturwissenschaften. 89 (10): 470–473. doi:10.1007/s00114-002-0361-8. PMID 12384723. S2CID 12091969.
- Pianka, E.R. (1995). “Evolution of Body Size: Varanid Lizards as a Model System” (PDF). The American Naturalist. 146 (3): 398–414. doi:10.1086/285806.
- McCurry, Matthew R.; Mahony, Michael; Clausen, Phillip D.; Quayle, Michelle R.; Walmsley, Christopher W.; Jessop, Tim S.; Wroe, Stephen; Richards, Heather; McHenry, Colin R. (2015). “The Relationship between Cranial Structure, Biomechanical Performance, and Ecological Diversity in Varanoid Lizards“. PLOS ONE. 10 (6): e0130625. doi:10.1371/journal.pone.0130625. PMC 4479569. PMID 26106889.
- Clemente, C. J.; Thompson, G. G.; Withers, P. C. (2009). “Evolutionary relationships of sprint speed in Australian varanid lizards”. Journal of Zoology. 278 (4): 270–280. doi:10.1111/j.1469-7998.2009.00559.x.
- King, D., Green, B., Knight, F. (1999). Monitors: The Biology of Varanid Lizards. Florida. Krieger Publishing Company.