James Cook University scientists think sea turtles may use the sunrise to show them the way home.

JCU scientists caught and tagged 22 turtles and transported them between eight and 28 kilometres from their usual home to study their navigational and orientation abilities.

Dr Takahiro Shimada says the research uncovered something unusual. 

“They frequently travel between areas that are a long distance apart and we know they are capable of travelling through unknown waters and returning to where they were captured,” Dr Shimada says.

“The most striking thing was the alternation of travelling and stationary periods.

“It appears the turtles reassess their heading direction in the hours around sunrise and adjust the direction of their movement accordingly.”

There is strong evidence turtles use geomagnetic and possibly wind or current-borne cues for orientation, but his study.

But Dr Shimada says his study may have revealed other factors help turtles navigate through the water.

“Orientation should not have been restricted to the hours around sunrise if geomagnetic cues, chemical cues and a cognitive map had been the exclusive sources of directional information,” he says.

“They may obtain critical cues for directing short-distance movement in the hours around sunrise given significant corrections were only observed to occur at this time of day.

“They may also use polarised light to recalibrate their internal compass at sunrise.”

“Our findings will advance understanding of the mechanisms of fine-scale orientation by sea turtles and in general provide valuable implications for animal orientation.”