Florida’s iguanas are a species introduced in the 1960s, and are not used to the freezing temperatures that the state currently experiences. As they usually sleep in trees, suffering a thermal shock can sometimes cause these animals to fall from the sky, a phenomenon typical of Florida.
Florida iguanas will have a unpleasant surprise: Temperatures plummeted across the southeastern United States. Overnight lows are expected to drop up to 2°Cor even values negatives in some areas of the state.
As green-iguanas (Iguana iguana) are not native to the US, but were brought to Florida in the 1960s, where they have mostly thrived — except, of course, when temperatures drop below 10°C.
These frigid conditions can cause a thermal shock in lizards. And as iguanas usually sleep in the treessuffering a thermal shock can sometimes cause animals fall from the skyin a typical Florida phenomenon.
These animals, which can reach more than meter and a half long, they are native to the rainforests of Central and South America, where temperatures are much more stable than in Florida.
“These tropical lizards were experiencing conditions they had never experienced in their entire evolutionary history, tens of millions of years,” he says. James Stroudevolutionary biologist at the Georgia Institute of Technology, at .
But in Florida, colder conditions occur every few years, although less frequently as temperatures rise due to climate change. “The experience of iguanas that were forced to brave the cold in the state could teach scientists more about how animals respond to new climates more generally,” says Stroud.
“We don’t have a great understanding of what happens when species or entire populations are confronted with completely new climates that they have never experienced before”, says the biologist.
Tropical lizards not native to Florida represent a rare example in the real world. During a cold snap in 2020, Stroud and his colleagues studied these critters and their rreaction to extreme temperatures.
In , published in Biology Letters, they found that lizards that had experienced more cold became more tolerant to low temperatures.
“Because they are extreme events, can be incredibly powerful by driving species responses at the population level,” says Stroud. Now he’s working to understand whether this tolerance could be an example of evolution — or simple adaptation.
If you live in Florida, Stroud says no need to worry about iguanas in thermal shock that you can see. Unless they fall from a height high enough to cause damage on impact, lizards they will probably be finehe states.
“Once the sun comes out and the air temperature warms up, it’s likely that they can actually wake up and become active again“, says Stroud. “You don’t have to put a blanket over them.”
