Nile Monitor Lizards: Invasive Species in Florida Threatens Native Species

Controlling Non-Native Nile Monitor Lizards in Florida

Nile Monitor Lizard basking: Photo by Thomas Sly

The first step for controlling the wild population of Nile Monitor lizards is for owners, especially those who can no longer care for their exotic pet, to be responsible. If they are unable to find someone willing to accept their lizard, then contact the Florida Fish and Wildlife Commission. This state organization has non-native pet amnesty days and accepts any exotic pet without questions. Owners need to remember that releasing any exotic pet into the wild is illegal.

Residents need to report any sightings of these reptiles to their local Fish and Wildlife Commission office. These lizards are aggressive and may pose a threat to small children, pets, and feral cats after their escape or release into the wild.  Their burrows are typically located along the shore line of canals, streams in urban areas, and golf course ponds. This invasive species is often seen basking in the sun near swimming pools, roofs, ponds, canals, sea walls, and grassy areas.

In an effort to eradicate Nile Monitors, the National Wildlife Research Center (NWRC) is investigating methods to control the spread of this invasive species capable of eating anything animal it can overpower and fit in its mouth. The NWRC is experimenting with Acetaminophen laced dead neonatal mouse and quail chicks as oral toxicant bait. Initial testing points to possible successful eradication efforts using these baits.

Residents should never attempt to capture a Nile Monitor lizard. When cornered they typically rear-up on their hind legs lashing out with sharp teeth, claws, and a strong tail. Their saliva is known to carry potentially lethal germs and pathogens, which may be fatal to humans. If bitten, seek medical attention immediately.


Campbell, T. [S.] 2003. Species profile: Nile monitors (Varanus niloticus) in Florida. Iguana 10(4):119-120

Enge, K. M., et al. 2004. Status of the Nile monitor (Varanus niloticus) in Southwestern Florida. Southeastern Naturalist 3:571-582

National Park Service and the Florida Fish and Wildlife Conservation Commission. Florida Invaders. Accessed July, 2011.

Somma. L. 2011. Varanus niloticus Fact Sheet. USGS Non-indigenous Aquatic Species Database, Gainesville, FL. Accessed July, 2011.

McGrath, S. 2005. Attack of the alien invaders. National Geographic 207(3):92-117.

© Copyright 2011 David R. Wetzel, Ph.D., All rights Reserved. Written For: Decoded Science
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  1. Alex says

    That photo you have is not of a Nile monitor at all. The first photo is of an Ornate monitor Varanus Ornatus which are perfectly legal in Florida. The second photo although not labeled as any specific species is a juvenile komodo.dragon. Kind of strikes me as odd that there are no actual photos of the correct species in the article. I’ve noticed that this tends to be the case with nearly every article on Nile monitors invading Florida. I don’t think many people realize that there are 70+ species of monitor worldwide. . To single out the Nile monitor and ignore all the other species of monitor invading Florida is absurd.

  2. Michael Kirsten says

    It’s not Always the Owners Fault!
    They Were Probably Set Loose When a Hurricane Hit Florida.Why Kill Them?
    I Own a Tame Female 5 foot Asian Water Monitor.She is both Very Curious and Intelligent. I Plan To Keep Her My Whole Life.I Know They Can Become Great Pets Because Like a Dog,My Lizard wears a Leash and Collor and Likes to Walk Around.I Have worked with reptiles for 14 Years and I am Part of the Reptile Club North Bay Herpetelogical Society.
    I Believe They Shouldn’t Be Killed Because It Wasn’t Their Fault.
    There Are Too Many Dogs and Cats,So Many That Most Are Just Put Down.These are Intelligent Reptiles and I Believe We Can Find Another Solution Without Killing Them!!!

  3. Graeme says

    Please if you capture any monitor lizards send them to me for my reptile breeding centre in South Africa.They’ll be used mainly to educate people and only ever keep in captivity.And never sold if breed outside of africa’s border.I’m stricked here at My “Tribal Reptile Breeding centre”that if you are deamed sutable to purchase one or more from me.That my stricked laws pertaining to the keeping of them are strickly adhered to.Here we need permits for them.I’ll go a step futher by taging each one recieved saterlite tracking responders.This is to insure none make there way outside the South African boarders.And any one trying to move them accross the South African boarders will be dealt with by the full extent of the law.

  4. RW Akile says

    We have Monitor Lizards here in Southern California as well. One at least has been living in the Baldwin Hills Area of Los Angeles. Luckily this one may be the ONLY one in its area. That does not count the possibility that one or some may well be living in the foothills adjacent to Los Angeles. Luck is it’s too cold in the mountains to sustain the reptiles found in Florida. The Coastal mountains are another story. Weather is mild never too cold or too hot.


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