The concern for people in South Florida is that these iguanas often sleep in trees, so when their bodies go dormant, they appear to fall from the sky onto streets, cars, pools, or even people walking around. And since iguanas are large — adult males can reach 5 feet in length, and weigh up to 20 pounds — this can be dangerous if one lands on top of you.
The invasive species can’t handle cold temperatures very well because they are cold-blooded. In general, iguanas begin to get sluggish or lethargic once the temperature drops below 50 degrees Fahrenheit.
Once the temperature drops below 45 degrees Fahrenheit the iguanas go into a dormant or cold-stunned state. They appear to be dead, but they are not. They remain breathing with critical body functions still operating.