George Romero did Night of the Living Dead; the Sunshine State is doing Day of the Falling Iguana. In a story that's prompted USA Today to insist "we're not making this up," the large lizards are reacting to a recent cold spell in the South in a way that may seem odd to non-Floridians: They're falling out of trees. The National Weather Service in Miami issued what CNN says is a rare warning on the phenomenon Tuesday, telling residents to "[not] be surprised" if an iguana drops onto the pavement in front of them. That's because iguanas, which are cold-blooded, get sluggish when temperatures dip below 50 degrees Fahrenheit—and when it gets to be colder than 45 degrees or so, their blood flow slows down so much that their bodies stiffen and they "fall out of the trees in which they frequent," a meteorologist tells USA Today.
It's been 10 to 15 degrees colder than usual for this time of year in the South, which means the iguana drop is in full force. But "don't assume that they're dead," a rep from the Florida Fish and Wildlife Conservation Commission says. A spokesman for Zoo Miami adds to the New York Times: "Even if they look dead as a doornail—they're gray and stiff—as soon as it starts to heat up and they get hit by the sun rays, it's this rejuvenation." Still, if the temperature remains super-chilly for many hours, the iguanas can die, especially smaller ones. Plus, because larger iguanas can grow to be up to 5 feet in length and weigh up to 20 pounds, a falling iguana can actually hurt someone. Florida residents hope they won't have to deal with this much longer: The NWS says that by Thursday, the temperatures around Miami should shoot back up into the 70s. (This isn't the first time this has happened.)