Nile Monitor (Varanus niloticus)
The Nile monitor is a large, nonnative lizard that has been introduced to Florida. A typical adult Nile monitor can grow over 5 feet in length and weigh close to 15 pounds. Nile monitors are light yellow to dark olive or brown in color. They have a pattern of light yellow chevron markings on the back, which appear as bands or stripes closer to the head and tail. The top side of the tail tapers up in the shape of a rudder to assist in swimming.
Nile monitors are semi-aquatic and are often found basking or foraging for food along canal banks in Florida. If encountered, they typically flee into the water. Once in the water, they can swim swiftly and stay submerged for an extended period. These reptiles are almost exclusively active during the daytime, spending nights sleeping in burrows or hiding in other refuges.
The Nile monitor is listed as a conditional species in Florida and cannot be acquired as a pet in the state.
The Nile River delta and Sub-Saharan Africa
Nile monitors are known to have breeding populations in Lee, Miami-Dade and Palm Beach counties. Observations of this species have been documented throughout the state, including multiple observations in Broward County.
Green iguanas were first reported in Florida in the 1960s in Hialeah, Coral Gables and Key Biscayne along Miami-Dade County’s southeastern coast. Green iguana populations now stretch along the Atlantic Coast in Broward, Martin, Miami-Dade, Monroe and Palm Beach Counties and along the Gulf Coast in Collier and Lee Counties. There have also been reports as far north as Alachua, Highlands, Hillsborough, Indian River and St. Lucie Counties. However, individuals observed in more northern counties are likely escaped or released captive animals and are unlikely to establish populations, as iguanas are not cold hardy. In cleared habitats such as canal banks and vacant lots, green iguanas reside in burrows, culverts, drainage pipes and rock or debris piles. South Florida’s extensive man-made canals serve as ideal dispersal corridors to further allow iguanas to colonize new areas.
History of introduction and management
Current populations in Florida were likely founded by escaped or released pets. The FWC is currently working with other agencies and organizations to assess the threat of this species and develop management strategies. The FWC is in the process of identifying populations of Nile monitors and removing them when possible. Officials periodically patrol and remove Nile monitors when sighted on state-owned and managed lands. Local government in Lee County operates a trapping removal program to remove Nile monitors sighted in the area. Federal government entities control the Nile monitor population at Homestead Air Reserve Base in Miami-Dade County.
Nile monitors feed on mammals, birds, reptiles, amphibians, fish and eggs.
Because Nile monitors eat such a varied diet, the FWC is assessing whether this species may have an impact on Florida’s native wildlife.