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Updates from the field, about the work of Bethany Augliere, including research, photography and writing.

Watch out for Falling Iguanas

Written and Photographed by Bethany Augliere

Cold-stunned Iguana in a South Florida parking lot. December 2022.

When cold weather hits Florida, it’s inevitable that news headlines begin circulating about falling iguanas, stunned from chilly temperatures. Why does this happen and what happens to the frozen reptiles?

The green iguanas (Iguana iguana) seen sunning themselves in South Florida are not native to the state, but rather to Central America, tropical parts of South America and some eastern Caribbean islands. They were first reported in the Sunshine State in the 1960s around Miami-Dade’s southeastern coast and the subtropical climate allows these large plant-eating lizards to survive, reproduce, and become part of the Florida environment.

Now, iguanas are considered invasive due to the damage they cause to residential and commercial landscape vegetation, and their impact on the local environment. For instance, in Bahia Honda State Park in the Florida Keys, green iguanas have consumed nickerbean, which is a host plant of the endangered Miami Blue butterfly, according to Florida Fish and Wildlife Conservation Commission (FWC). They also cause damage to infrastructure, such as seawalls and canal banks, by digging burrows.

Why Do Iguanas Fall From Trees in Cold Weather? 

Iguanas are cold-blooded reptiles, which means they depend on the sun and basking to take in heat and get warm. They are comfortable at around 73 degrees Fahrenheit, and thrive at 95 F. Below about 40 F (5 C), the iguanas become immobile due to a lack of blood flow, so their muscle control temporarily shuts down. That’s why you might hear about falling iguanas from trees, they lose their grip when their body becomes immobilized.

According to experts, whether or not iguanas die from cold snaps depends on how low temperatures get and the amount of those temperatures are sustained.

What To Do If you Find a Cold Iguana?

FWC urges Floridians not to bring the reptiles home or into their cars. The animals can recover quickly once warmed up and use their long tails and sharp teeth and claws when defensive. Also, don’t relocate or release green iguanas (or any nonnative species) – it is illegal and can harm native wildlife. It’s actually illegal to possess a green iguana without a permit, as they are listed as a Prohibited species. For more information about iguanas, technical assistance for homeowners – including techniques to discourage iguanas from frequenting your property, and a list of wildlife trappers can be found at MyFWC.com/Iguana.

Originally posted: Vero Beach Portfolio Mag