Hurricane Blows and Lizard Toes: Rapid Evolution at Work

Biologist Colin Donihue has probably watched more lizards get blown off sticks by heavy winds than any other person. It’s all part of an experiment in his quest to understand rapid evolution.

Donihue is a researcher at Washington University in St Louis. For the past decade, he has set up the test many times. A Silver Key anole lizard is placed on a rod. Once it’s clinging to the wood, Donihue turns on the fan. The lizard holds on as long as it can as the fan hits it with winds up to 100 miles per hour. Donihue records the lizard’s efforts with a high-speed camera. When it lets go and falls into the soft padding beneath the rod, Donihue records how long it held on.  

The anole lizards are native to Turks and Caicos. The purpose of the trials is to see if the twin hurricanes that hit the islands in 2017 changed their evolution. Donihue's study shows they did.

“The population that had been hit more by hurricanes tended to have larger toepads than those that had been hit less,” Donihue told The Wildlife Society in 2020. Donihue and a research team found the lizards that hung on during hurricanes had shorter back toes than other anoles. That, along with the stronger toepads, may have allowed certain lizards born with the right foot-shape to survive. Later, they would pass along their genes. The team published their findings in August in the journal Current Biology.  

The team tested the DNA of the Silver Key anoles. They found the lizards had a gene unlike those of other anoles. In less than 10 years, the lizards seemed to have evolved. They had changed to better survive in a world where hurricanes are stronger and more frequent. It's an example of rapid evolution.           

Reflect: Why do you think only some animals survive extreme weather events while others don't?

Photo of a Graham's anole (one of the species included in the study) in Jamaica from Wikimedia Commons courtesy of jpockele.