Why do Iguanas Fall From Trees When it’s Cold?

While overzealous South Floridians are preparing for the new year by breaking out their puffer coats and Uggs, which many do anytime the temperature flirts with the 60s, something even more cartoonish is happening: Frozen iguanas are falling out of trees.

Yes, you read that right: Iguanas. Plummeting. From. Trees.

A word to the uninitiated: Before you start picturing a scaly apocalypse, let’s clear up why these Jurassic Park extras are falling from the sky and why Floridians seem to roll with it like everything’s normal. The temperature dropped to the 40s early Wednesday morning, which seasoned Miami-area residents know means it’ll be chilly with a chance of raining iguanas. Or would it be hailing iguanas? 

Any time the weather drops, South Floridians, ever the chroniclers of weird weather phenomena, immediately take to X, the platform formerly known as Twitter, to share proof of the fossilized miniature dinosaurs. 

The Florida Fish and Wildlife Conservation Commission (FWC) also posted on X about the phenomenon. FWC advises the public not to bring stunned animals indoors, keep them away from household pets, and avoid relocating them.

“South Florida today… don’t step on the fallen iguanas. They aren’t dead. They are just hibernating,” one user wrote.

Another post, featuring a motionless iguana reluctantly resting on a paved road, was more succinct: “South Florida temperature gauge.”

Falling Iguanas: The Science of the Drop

Green iguanas are cold-blooded reptiles, meaning their internal thermostat depends entirely on the weather. When it’s sunny and 75, they live their best lives, sprawling across seawalls and feasting on nickerbean (AKA gray nicker), the host plant of the endangered Miami blue butterfly. But when the mercury falls below 50 degrees Fahrenheit, it’s game over – or at least a temporary pause. The iguana’s body goes into a cold-induced paralysis, leaving it frozen in place or, more often than one might imagine, falling out of trees.

This phenomenon, known as “cold-stunning,” explains why your backyard may suddenly resemble an iguana obstacle course during a Florida cold snap.

What Should I Do if I See a Frozen Iguana?

According to the Florida Fish and Wildlife Conservation Commission (FWC), it’s best to let nature take its course. Don’t bring a cold-stunned iguana indoors – it might recover quickly and, once thawed (as it were), might not appreciate your hospitality.

The FWC encourages homeowners to humanely euthanize iguanas on their property, as they’re considered an invasive species. But the agency-specified killing methods [Editor’s note: Don’t say we didn’t warn you] — i.e., a two-step process that requires an air gun or captive bolt, followed by a screwdriver through the skull “using deliberate, multi-directional movement, ensuring destruction of the entire brain” — might not be your idea of a fun cold-weather family activity.

Furthermore, the FWC has declared green iguanas a “Prohibited Species,” banning the sale, breeding, and ownership of new pets with few exceptions. Existing pet owners must microchip their iguanas and apply for permits.

A Quirky Florida Reality

While an iguana landing on you might feel like a scene straight out of a cartoon, Zoo Miami communications director Ron Magill says you’re more likely to be bitten by a stray dog. Some unfortunate souls – like the Miami yogi whose savasana was interrupted by a 20-pound green iguana to the noggin – might argue otherwise.

So, as South Floridians look forward to the inevitable (if occasional) winter chill, remember to grab your sweater and keep an eye on the trees because there’s always a chance for a passing cold front to bring scattered iguana showers.