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How Baby Sea Turtles on Treadmills Can Help Researchers Understand Wild Turtle Survival

No doubt it’s adorable, but the study offers clues into the impact of disorienting light pollution on the reptiles’ health

"I'm swimmering! For science!" (Jay Paredes)
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They're baby sea turtles. They're wearing swim suits. What more do you need to know? Well a lot, actually. As Elaina Zachos reports for National Geographic, though they're certainly adorable, these tiny tots could help researchers better understand the impacts of light pollution on baby turtle survival after they make their break from the safety of their nest to the open ocean.

Sea turtles build their nests right on the beach to give the itsy-bitsy hatchlings a fighting chance to flipper themselves into the ocean. They have a lot of predators—gulls, crabs, raccoons and more—that would love to gobble them up like tourists at a buffet. But if all goes well, a hatching can make it into the ocean within a few minutes, likely drawn to the brightest light on the lowest horizon.

But in this modern world, lights are everywhere, and the tiny reptiles can get disoriented and take a more circuitous route to find water. This exhausting venture can sometimes last hours. How does all that exercise affect the little creatures once they make it to water? Researchers at Florida Atlantic University decided to put some baby turtles to the test to figure it out.

“We wanted to know if they would even be able to swim after crawling 500 meters [1,640 feet] or more, which could take them as long as seven hours to complete,” biologist Sarah Milton says in a press release

So along with biologist Karen Pankaew, Milton collected 150 newborn loggerhead and green sea turtles from Palm Beach County, Florida. They then exercised each turtle in the lab using a custom-built herp treadmill with a light suspended in front of the device to attract the little critters. In one test, they simulated the long distances disoriented animals might walk on the beach, keeping the babies marching for 656 feet. In another, they had them scramble 1,640 feet.

After the workout, the researchers then fitted the turtles into little swimsuits connected to a harness and put them in a tank of water, observing how they swam for two hours. Meanwhile, the researchers measured vital signs like oxygen consumption, glucose, plasma lactate levels as well as the number of swimming strokes they performed.

The team also conducted field studies, following baby turtles on the beach and measuring the distances they traveled, how long it took them, and how often they rested to ensure their treadmill study simulated reality. They detailed their results this week in a study published last month in The Journal of Experimental Biology.

What they found is that the tiny turtles are incredibly tough. “We were completely surprised by the results of this study,” Milton says in the release. “We were expecting that the hatchlings would be really tired from the extended crawling and that they would not be able to swim well." That turned out not to be the case. "They are, in fact, crawling machines," she says. "They crawl and rest, crawl and rest and that’s why they weren’t too tired to swim.”

While that’s good news for the turtles, it doesn’t mean light pollution isn’t hurting them. The authors note that spending more time on the beach either walking or resting raises the potential that the turtles will be eaten by predators, lured into a swimming pool or head into downtown Miami.

David Godfrey, executive director of the Sea Turtle Conservancy who was not involved in the study, tells Zachos that the study provides great new information but has some limitations. For instance, in Florida, once the turtles hit the ocean they need to make an epic 30-mile swim to reach the jet stream, where they are relatively safe.

While the researchers were only allowed to observe the turtles for two hours post-workout before returning them to the beach, watching them for 24 hours might show different results. Milton agrees that it would be beneficial to watch the turtles longer—and so do we. Any scientific reason for putting a bathing suit on a baby turtle is alright by us, especially if there's a web cam so we can watch.

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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