Researchers have found an important new clue in the sea turtle's "lost years" mystery.
New findings suggest that sea turtles are very active swimmers even at a tender age of six-18 months, and they do not just passively drift in ocean currents as researchers once thought.
Where exactly turtles travel in their first years of life, before returning to coastal areas as adults to forage and reproduce, has puzzled scientists for decades.
"With a better understanding of swimming behaviour in these yearlings we can make better predictions about where they go and what risks they might encounter," said lead author Nathan Putman from National Oceanic and Atmospheric Administration.
Upon hatching, young sea turtles swim offshore and disperse with the help of ocean currents.
The turtles are rarely observed during the next two-10 years or so. Not much is known about these juveniles' movements during this time and researchers dub it the "lost years".
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But it has been widely assumed that turtles simply drift with ocean currents. In the new study, researchers placed specially designed solar-powered tags on 24 green and 20 Kemp's ridley wild-caught sea turtle toddlers in the Gulf of Mexico.
The tags were tracked by satellite for a short period. Next to the turtles, they deployed small, carefully-weighted/passively-drifting surface buoys that were also tracked by satellite.
When the drifter tracks were compared to the sea turtles' movements, the researchers found that the turtles' paths differed significantly from the passive drifters.
Using observed and modelled ocean current conditions, they found a difference of distance between the turtles and drifters to be as much as 200 km in the first few days.
In nearly every instance, the toddlers' swimming behaviour appears to help them reach or remain in favourable ocean habitats.
"The results of our study may ultimately lead to new ways to protect these endangered animals," said co-researcher Kate Mansfield from University of Central Florida.