Well, it’s the Sunshine state. We call it that for a reason. Outside of maybe a handful of days in the dead of winter, it’s warm and sunny year round down here. That makes this place a haven for reptiles. And we do, in fact, have a beautiful range of them in this state. The issue comes from invasive species. Due to the pet trade, people bring in reptiles from other countries. Many times, these reptiles get lose and form populations. That’s why today we’ll be discussing one of those reptiles: the Nile Monitor.
Nile Monitor: Overview
Nile Monitors are carnivores, and they are extremely good predators. They’ll eat anything – fish, turtles, mollusks, birds, mammals, and eggs. They live in burrows in the ground, generally near canals. They are excellent swimmers, able to hold their breath for up to an hour, and can run up to 18 mph on land. Nile Monitors can grow to 7 feet long, so the potential harm to wildlife in the area – including burrowing owls – is great.
The Nile monitor (Varanus niloticus) is a semi-aquatic lizard that is not native to Florida. Nile monitors are olive-green to black in color and have cream-colored or yellow stripes on the jaw and head. They have rows of yellowish, V-shaped stripes beginning at the base of the skull and neck which transform into bands or spots along the back. Their lightly banded tails are usually 1.5 times the length of their bodies and are shaped like a rudder to aid in swimming.
Nile monitors may be observed basking on rocks and branches and are often seen in or close to water. They are mostly active during the day. At night they may sleep on branches or submerged in water in warm weather or retreat to burrows in cooler weather. Nile monitors are skillful climbers and adept swimmers. They can remain underwater for 12-15 minutes.
Female Nile monitors reach sexual maturity at about 2 years or when they attain lengths of about 14 inches. Eggs are typically deposited into burrows, and clutches consist of 12-60 eggs depending on the size of the female, with larger females laying more eggs. Males will mate with many different females and engage in fierce wrestling competitions with other males for mating opportunities. Nile monitors can live up to 20 years in captivity. They are the largest lizard species in Africa and can attain lengths of about 6.5 feet and weigh up to 17.8 pounds, although a typical adult averages 5 feet in length and weighs close to 15 pounds.
An aggressive invader
Currently, the four largest species of lizards established in Florida are nonnative species. One of these large lizards, the Nile monitor (Varanus niloticus), can grow to more than six feet in length and is native to sub-Saharan Africa. Nile monitors are known to have breeding populations in Lee and Palm Beach Counties, but evidence suggests that established populations may also exist in Miami-Dade and Broward Counties. Nile monitors are strong swimmers, climbers, and generalist predators. They are known to prey upon aquatic and terrestrial invertebrates and vertebrates, and the eggs of reptiles and birds. This makes them a threat to native wildlife, including endangered and threatened species like American crocodiles, sea turtles, and burrowing owls.
Nile monitors are generalist feeders and hunt for prey on the surface, below ground, in trees and in fresh and saltwater (Losos and Greene 1988). Their broad diet includes crabs, crayfish, mussels, snails, slugs, termites, caterpillars, beetles, spiders, grasshoppers and crickets, fish, frogs, toads, lizards, turtles, snakes, young crocodiles, and other reptiles, birds and their eggs, and small mammals.
South Florida’s extensive canal system may provide dispersal corridors for the species, which tends to inhabit water edges. Researchers believe populations of Nile monitors in Florida stem from intentional and unintentional releases from animals in captivity. Nile monitors may escape confinement by pushing off the tops of cages or by using their sharp claws to tear through screens. They may be intentionally released if they become difficult to feed, manage or handle or if they are deemed unfit or too sick to sell in the reptile trading industry. Nile monitors may also escape from facilities destroyed by hurricanes.
Nile Monitor Removal
You can probably assume that it’s dangerous to just think you can move this yourself. This is a fast, powerfully built lizard with a tail that cracks like a whip and long, curved claws. Not to mention its teeth! Monitor lizards all believed to have some sort of anticoagulant in their blood. And so, they won’t really be able to kill you. But- a bite will make you bleed. A lot. And, like any other animal, they will aggressively defend themselves when threatened.
The Nile Monitor is listed by the state of Florida as a conditional species. This just means that you shouldn’t own one as a pet. Not only that, but you need a permit to even possess or import this species. And then, you need a license to display or research it- such as at a zoo.
The FWC encourages you to report Nile monitor sightings. This is an invasive species that we want to reduce the numbers of. That doesn’t mean if you see one you should just go out and shoot it. Instead, you can help by taking a picture, writing down the location, and reporting this info to the FWC. You can report them online at IveGot1.org. And, of course, as I said above, do NOT attempt to try and catch these yourself.
