But fear not, the scaly skydivers are not dead—they are just cold.

“Iguanas are cold-blooded and at night with no sun to provide solar warmth, they become torpid, unable to move,” William Kern, a professor and reptile expert at the University of Florida, told Newsweek.

As a result, the iguanas lose their grip and fall out of the trees which they call home.

During the cold snap in early January, many users took to social media to share photos of the strange phenomenon.

“Still alive … just slow and stunned from the cold temperatures,” said one user in an Instagram post showing a large, sluggish green iguana.

When the weather is cold but sunny, the reptiles can gain enough heat from the sun to increase their body temperature.

But when it is overcast, this can be a lot harder. “The most notable episode was in January 2010,” Kern said. “We had an extended cold spell for a week; lows in the upper 30s to low 40s. It was overcast for almost the entire week and the iguanas had no opportunity to bask and warm up.

“This unusual set of conditions caused extensive mortality to green iguanas. Several times since then, we have had nighttime temperatures that stunned the iguanas and if it was windy due to the cold front, stunned iguanas fell off the branches.”

Kern said that, under these conditions, it was not unusual to find stunned iguanas on the ground. When the weather returns to normal, the fallen iguanas can warm their bodies once again and return to business as usual.

“Usually we have bright sunshine on the days after the front passes so the iguanas can bask, warm up, and climb back into the trees,” Kern said.

With temperatures in much of Florida expected to tumble this week, Kern said falling iguanas were likely to be a feature of this festive season.

Green iguanas are not native to Florida. They are an invasive species which are often considered a nuisance by property owners.

Kern said if you find a frozen iguana, it is best to avoid moving it with your bare hands: “If you don’t plan to euthanize them as part of an invasive species removal program just move them to a sunny spot and they’ll recover.

“This can be hazardous, as even a very slow iguana can scratch severely unprotected hands and arms. I use heavy gauntleted welders gloves or leather work gloves. A shovel may also be used.”

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