Does Climate Change Threaten Florida Gator Reproduction? One UNF Biologist Is Trying To Find Out

Jul 2, 2018

As the world warms, populations of certain male reptiles are declining and that could spell extinction for alligators in the Sunshine State.

One University of North Florida scientist is hatching hundreds of gators to try and track the phenomenon.

In the summer of 1993, the film Jurassic Park introduced audiences to a very reptilian talent — the dinosaurs could change sexes.

And that’s not just science fiction. Just like in the world of Dr. Ian Malcom, reptiles can change sex in response to their environments and scientists fear a warmer world could trigger the change on a mass scale.

University of North Florida biologist Adam Rosenblatt, who’s incubating 400 Louisiana alligator eggs atop

Credit Adam Rosenblatt / University of North Florida

 a school building, explained one way how.

“Whether you’re a male or a female in those reptile species is determined by the temperature of the nest. So, what we’re doing here is we’re trying to replicate what [a] future climate change scenario might be,” he said.

Female alligators naturally outnumber males in the wild, but Rosenblatt said rising area temperatures could mean all new hatchlings will be female — an effective extinction. To have a healthy mix of male and female alligators, temperatures should hover in a sweet spot, not too cold and not too hot. Otherwise, females will vastly outnumber their male counterparts.

Scientists in Australia have already begun to record the types of affects in two other reptile species. Like alligators, a sea turtle’s sex is determined by the temperature of an egg’s incubation period. In one specific area of the continent, one study found female turtles now outnumber males there 116 to 1, reported National Geographic. In another area of the land down under, bearded dragons have been documented changing sex after birth as a response to a warming climate, Business Insider reported.

Rosenblatt said these effects have not yet been recorded in American alligators and that extinction of Florida’s most feared and beloved reptile could be especially detrimental to the state’s overall ecology and economy.

“They’re the top predator, right? They’re the largest predator in the areas that they live in, they eat lots of different kinds of prey and repeatedly research has shown that if you lose a top predator from an ecosystem, that ecosystem can change very dramatically,” he said.

Aside from the weakening of the Sunshine State’s food chain, Rosenblatt also said the industry built on the scaly backs of this apex predator nets the Florida gator hunting program around $2 million a year.

Rosenblatt has 20 nests with 20 eggs in each, worth a combined $20,000 he said. Using plastic wrap or chicken wire, he allows for the nests to be warmer or cooler. Sometime in early to mid-August, the baby gators should hatch. The UNF biologist hopes to expand his experiment with other populations of gators from around the country.

According to the National Oceanic and Atmospheric Administration (NOAA), the worst-case projections for Duval County are around 140 days per year of 90-degree-or higher heat by 2030. According to an average of NOAA-recorded temperatures between 2010 and 2013, the county saw around 52 of these days annually.