When baby sea turtles are born, within their first 24 hours they make the journey from nest to ocean. The trek should take a few minutes, but it sometimes lasts hours in urban settings where artificial light can disorient the hatchlings. Two Florida Atlantic University (FAU) scientists employed wee treadmills and little swimsuits to dig into the turtles’ swimming performance after crawling for so long – and they were surprised by what they found.
Speed is crucial for turtle hatchlings, who face dangers on their way to the ocean. Their survival “depends heavily on their ability to swim,” according to FAU. But in urban settings, excess light from streets and buildings can draw the babies away from the ocean and towards land – where they might get run over by traffic, drown in a pool, or be eaten by a predator. Biological sciences associate professor Sarah Milton said in a statement, “What prompted our study was the desire to understand what happens to these hatchlings after they spend hours crawling on the beach because they are disoriented. We wanted to know if they would even be able to swim after crawling 500 meters or more, which could take them as long as seven hours to complete.”
Milton and graduate student Karen Pankaew conducted what FAU described as the “first study on disorientation to examine the physiological effects of extended crawling and swimming performance.” They gathered 150 hatchlings from 27 loggerhead and 18 green turtle nests in Palm Beach County, Florida. The hatchlings walked on tiny treadmills before swimming in a tank in a specially designed swimsuit. The scientists measured oxygen consumption, lactate accumulation, and swimming breathing and stroke rates. Field studies supplemented laboratory observations. The hatchlings were placed into the ocean in their natural habitats shortly after collection.
The study results completely surprised the researchers, according to Milton, who said, “We were expecting that the hatchlings would be really tired from the extended crawling and that they would not be able to swim well. It turned out not to be the case and that they are in fact crawling machines. They crawl and rest, crawl and rest and that’s why they weren’t too tired to swim.”
She also said the study offers a scientific basis to back up lighting ordinances during hatching season.
The Journal of Experimental Biology published the study in November.