Temperatures in the otherwise sunny state of Florida have dipped so low that immobilized iguanas risked falling from trees, the United States National Weather Service for Miami-South Florida warned on Sunday.

The weather service pointed out that iguanas are cold-blooded lizards and slow down when temperatures dip to between 4 and 9 degrees Celsius (roughly 40 to 50 degrees Fahrenheit).

The weather service also warned people not to jump to the wrong conclusions should they come across any of the stunned animals.

"They may fall from trees, but they are not dead," the service tweeted.

Temperatures in South Florida dipped below minus 3 degrees Celsius (25 F) on Sunday morning, according to the National Weather Service — unusually cold winter weather for the region. The high is expected to be between 10 and 15 degrees Celsius (50 to 60 F).

Freezing rain and powerful winds pummeled much of eastern US over the weekend, with most states urging people to stay home as heavy snowfall reduced visibility and ground air travel to a halt. Tens of thousands of people also lost power at the height of the storm.

What happens to iguanas in the cold?

Zoologist Stacey Cohen, a reptile expert at Palm Beach Zoo in Florida, told a local news station that iguanas lose their ability to hang on to trees if it gets too cold. They usually sleep in the trees when it starts getting cold but lose control of their bodies after a certain point.

Although most of the reptiles will likely survive the period of immobilization, Cohen also said freezing temperatures did comprise a threat to their survival.

"Cold is very, very life-threatening thing for them because they are from parts of Central and South America close to the equator where it always stays warm," Cohen told West Palm Beach News and Weather station.

Green iguanas, which can weigh up to 7.5 kilograms (17 pounds) and measure more than 1.5 meters (around 5 feet) in length, are not native to Florida, according to the Florida Fish and Wildlife Conservation Commission. They were introduced as stowaways in cargo ships and are considered an invasive species. 

Elsewhere this winter, hundreds of thousands of farm fish died from thermal shock in a lagoon in northwestern Greece last week.

Animals have various mechanisms to cope with the cold. While some species like the fire-colored beetle can withstand temperatures of minus 30 degrees Celsius (minus 22 F), other mammals such as marmots hibernate to protect themselves from the cold.

rm/msh (Reuters)