No, it’s not the plot of some schlocky horror movie from the ’70s. In fact, this is a phenomenon already well known by residents of Miami and surrounding areas, and it happens mostly when a cold spell hits the region. Iguanas aren’t designed to handle temperatures under a certain limit, but that doesn’t mean they die as soon as it gets chilly. They just sort-of shut down.
Everyone knows reptiles are cold blooded. That is to say, they need environmental warmth to carry out normal metabolic processes – they can’t generate their own. You’ll never see a lizard running a fever. That also means that, when they run out of sunlight, their systems shut down to such an extent that they may appear dead, and they lose grip on whatever they’re holding on to. In the case of iguanas, that’s most likely a tree branch. Hence, the recent rain of lizards in the Florida region. However, this phenomenon is closer to a sort of hibernation than to actual death, especially in the case of larger iguanas. And the largest ones can be up to 6 feet long. As soon as they get a healthy dose of sunlight and warmth, they can snap out of this catatonic state and be on their merry way.
You’d think that iguanas would have no business living in an area where they run the risk of almost freezing to death once a year. And you’d be right – neither iguanas, nor Burmese pythons for that matter, belong in Florida. But they’re there, because of us humans. A 2010 cold snap was the first weather event that could put a serious dent in the population of these invasive species. 2017 seems to be another such year.
However, if you live in Florida and happen to find a grey-ish, shriveled iguana on your driveway, don’t assume it’s dead. If you’re feeling charitable, get it out of harm’s way – sometimes poking it with a shovel for example, can wake the animal up. You can safely assume the lizard is dead once it’s turned dark brown, bordering on black.
