Florida Lizards Evolve in Just 15 Years

A native lizard species from Florida has demonstrated some rapid evolution - in as little as 15 years - due to pressures from an invading lizard species hailing from Cuba, according to a recent study.

Fearful of invading Cuban anoles or brown anoles, the native lizards reportedly began perching higher in trees, and, generation after generation, their feet evolved to become better at gripping the thinner, smoother branches found higher up.

The change occurred so quickly, that just within a matter of months all members of the species began shifting their sights higher up. It was just a matter of time until just 15 years and 20 generations later, their toe pads had become larger, with more sticky scales on their feet.

"We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising," researcher Yoel Stuart, the study's lead author, said in a statement.

To put this in perspective, researchers say that if human height evolved as fast as these lizards, the average American man, standing 5 feet 9 inches tall, would soon shoot up to 6 feet 4 inches within 20 generations. That's about the same height as an NBA shooting guard, Stuart said.

"Although humans live longer than lizards, this rate of change would still be rapid in evolutionary terms," he added.

The rapidly evolving lizards in question, called Carolina anoles or green anoles, are common in the southeastern United States. Their peaceful existence was then shattered in the 1950s when brown anoles first started showing up, possibly as stowaways in agricultural shipments from Cuba. They have since spread across the southeastern United States and have even jumped to Hawaii.

This latest study, published in the journal Science, demonstrates just one of very few examples of "character displacement," in which similar species competing with each other evolve differences to take advantage of different ecological niches.

For example, two species of finch in the Galápagos Islands diverged in beak shape as they adapted to different food sources. In the case of Carolina and green anoles, they developed stickier scales to better grip towering smooth branches to inhabit higher perches.