Messing with Paradise: Iguanas

Iguana
3.21.05
Photo by Mark M.

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NON-NATIVE, EXOTIC and INVASIVE

From the University of Florida:

Introduction

Due to Florida's prominence in the exotic pet trade, iguanas imported as pets have escaped or been released, and are now established in South Florida. This has created unique problems for Florida's homeowners and businesses. South and Central Florida's subtropical climate allows these large herbivorous (plant-eating) lizards to survive, reproduce, and become part of the Florida environment. Three large members of the iguana family (Iguanidae) have become established in south Florida. These are the common green iguana (Iguana iguana), the Mexican spiny-tailed iguanas (Ctenosaura pectinata) and black spiny-tailed iguana (C. similis). Large male spiny-tailed iguanas are often misidentified as alligators by startled homeowners because of reduced dorsal spines and dark color. There are many other large lizards established in Florida that some people misidentify as iguanas. The brown basilisk (Basiliscus vittatus) is a large (up to 2 feet) lizard that is often mistaken for an iguana and occurs in the same areas as introduced iguanas. Knight anoles (Anolis equestris) commonly reach between 12-18 inches. Jamaican giant anole (Anolis garmani) males can reach 12 inches. People in South Florida often call these large green anoles "iguanas" or "iguanitos." Occasionally escaped pets that have not established breeding populations are seen by surprised neighbors. These include large lizards like many of the monitor lizards (Varanus sp.).

Habits

Adult iguanas are herbivores' feeding on foliage, flowers, and fruit. They will occasionally eat animal material such as insects, lizards and other small animals, nestling birds and eggs. Juveniles eat more animal material, especially insects, and hatchling green iguanas eat the droppings of adult iguanas to acquire the gut bacteria that help them digest plant material. Males are territorial against other males, but are not territorial against females and juveniles. These large lizards like to bask in open areas; sidewalks, docks, seawalls, landscape timbers, or open mowed areas. If frightened, they dive into water (green iguanas and basilisks) or retreat into their burrows (spiny tailed iguanas). This habit of diving into the water to escape makes green iguanas very difficult to capture. Basilisks and anoles generally eat insects and small vertebrate prey, but Knight anoles occasionally eat small fruits and flowers as well.

Damage

Damage caused by iguanas includes eating valuable landscape plants, shrubs, and trees, eating orchids and many other flowers, eating dooryard fruit like berries, figs, mangos, tomatoes, bananas, lychees, etc. Iguanas do not eat citrus. Burrows that they dig undermine sidewalks, seawalls, and foundations. Burrows of iguanas next to seawalls allow erosion and eventual collapse of those seawalls. Droppings of iguanas litter areas where they bask. This is unsightly, causes odor complaints, and is a possible source of salmonella bacteria, a common cause of food poisoning. Adult iguanas are large powerful animals that can bite, cause severe scratch wounds with their extremely sharp claws, and deliver a painful slap with their powerful tail. Iguanas normally avoid people but will defend themselves against pets and people that try to catch them or corner them.

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