Nile Monitors in Florida

​About the Author:
Jenna is a graduate student studying Wildlife Ecology and Conservation at the University of Florida. Her primary work is research, control, and removal of nonnative and invasive animals found throughout south Florida.

To keep with the theme of "animals that don't belong in Florida" I would like to introduce the Nile Monitor. Nile Monitors (Varanus niloticus) are large African lizards, which have been introduced in Florida via the pet trade - just like everything else, what a surprise. These carnivorous lizards can grow up to 8 feet in length, and weigh a whopping 30 pounds! They are diet generalists - meaning they will eat pretty much ANYTHING. I personally have been looking at some of their diet items, and they range from reptile eggs, to turtle, insects, small mammals, frogs, toads, and snakes! 

These lizards were first noticed in Florida in the 1990s, and there is a heavy threat these lizards pose to a protected native species. In Africa, Nile Monitor are known to raid crocodile nests and feed on crocodile hatchlings - this feeding habit directly implicated Nile Monitors as threats to Florida's native American Crocodile. The American Crocodile is a protected species, and are recovering from a steep population decline that hit its lowest in the 1970s. Established populations of Nile Monitors could make it even harder for these crocodiles to recover.

These lizards are sold in the pet trade despite their rather aggressive demeanor.  They are certainly not for beginners. To quote a book:

"There are few of these lizards less suited to life in captivity than the Nile monitor. Buffrenil (1992) considered that, when fighting for its life, a Nile Monitor was a more dangerous adversary than a crocodile of a similar size. Their care presents particular problems on account of the lizards' enormous size and lively dispositions. Very few of the people who buy brightly-coloured baby Nile Monitors can be aware that, within a couple of years, their purchase will have turned into an enormous, ferocious carnivore, quite capable of breaking the family cat's neck with a single snap and swallowing it whole."
-Bennett, D. 1995. Little Book of Monitor Lizards, Viper Press, Aberdeen, UK

As if their attitude wasn't enough, these lizards have huge appetites, require large space for housing (hello- they can grow to be 8 feet long...a tank over 16 feet in length would be required to comfortably house a lizard of that size!), and a very secure space at that. These animals also really enjoy swimming, climb, and dig - so pet owners should be ready to build an outdoor enclosure or dedicate a whole bedroom to their animal. This, of course, is why monitors are now a problem in Florida. The requirements the need to be kept, as well as the rude personalities, lead to owners becoming fed up, tired of, or just plain scared of their pet Nile Monitor. That is how they became to live in Florida - released pets.

To learn more about Nile Monitors as pets: 

https://www.thespruce.com/nile-monitors-1239213

To learn more about Nile Monitors as threats:

​https://www.decodedscience.org/nile-monitor-lizards-invasive-species-in-florida-threatens-native-species/1962

http://myfwc.com/wildlifehabitats/nonnatives/reptiles/nile-monitor/

http://www.evergladescisma.org/the-dirty-dozen/nile-monitor/

All photos belong to Nick Scobel:  https://www.flickr.com/photos/michiganherper/