Leaping Lizards Evolving Faster in South Carolina Due To Cuban Invasion

While humans have experienced a long-standing, contentious relationship with Cuba  — dating all the way back to JFK and the Bay of Pigs crisis of the early 1960’s — who knew other animal species might also have similar turf wars? Well . . . such a case has arisen between the American green anoles and the Cuban brown anoles.

The Anolis Carolinensis are found on the southeast coast of the U.S., from South Carolina down to Florida -- and they have a bone to pick with their non-American counterparts. In just 15 years — or 20 lizard generations — green anoles are evolving at an exponential rate to contend with an invasion by aggressive brown anoles from Cuba [aka the Anolis Sagrel.] Based on territorial skirmishes, these two species are at odds, and here are the reasons why.

Why Can’t We All Just Get Along?

Similarly as to how skin pigmentation has caused racial divides amongst Americans over the years, it appears that a similar type of divide exists with these lizards.  Brown anoles and green anoles compete for food [namely insects] and they will also eat one another's young. To avoid potential ongoing clashes, green anoles took to higher ground. By moving to the higher parts of trees, they evolved larger, stickier toe pads to help them get a better grip on their newfound habitat, Science Daily reports.

Brown anoles first appeared in South Florida, possibly as stowaways in agriculture shipments from Cuba, and have since spread across the southeastern U.S. Both use camouflage to their advantage. While the green anoles are now located in the higher and greener branches, the brown anoles stay closer to the trunk of trees blending into the bark.

As The Scientist reported, researchers have studied green anoles' behavior and physiology before and after the introduction of a few of their Cuban rivals and monitored those populations for 15 years. "By August 1995, after just three months, the Carolina anoles began perching at greater heights.”

Who’s Stepping on Who’s Toes?

When the lizards' toes started to grow in size, shape and stickiness, the scientists performed tests in the lab to see if those traits were inheritable. They determined that offspring of larger-toed individuals did indeed inherit that trait in the lab.

The research team expected to see some change in the green anoles due to the increased competition, but the extremity of that shift—referred to as character displacement—caught them off guard. "To put this shift in perspective, if human height were evolving as fast as these lizards' toes, the height of an average American man would increase from about 5 foot 9 inches today to about 6 foot 4 inches within 20 generations!

Now if only the National Basketball Association [NBA] could figure out this evolutionary trick to increase the height of their players — leaping lizards . . .  we’d have shooting guards in the 8 foot range, in no time!

 

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