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Landscape of no fear: Sea turtles don't avoid hungry tiger sharks the way you'd think

Sea turtles don't alter their movements to avoid shark attacks, researchers find, which means sea turtles are tougher than most of us.

Tiger sharks (Galeocerdo cuvier) are common visitors of the reefs north of the Bahamas in the Caribbean. Getty Images/Cultura RF

If you are a sea turtle (and if you are, please tell us how you got on the Internet from the ocean when we can barely keep our Internet connections running on dry land), you've got a lot to fear from the tiger shark. It likes you as prey.

However, based on a new study, it seems that sea turtles don't let the threat of being eaten alive interrupt their lives.

The study, published in the August issue of the online journal Ecology, found that even if tiger sharks move into an underwater neighborhood to be closer to their food source, turtles just keep on surfacing and exposing their vulnerable parts like everything's normal.

Researchers from the Rosenstiel School of Marine & Atmosphere Science at the University of Miami came to this conclusion by tracking these predators and their prey in the Northwest Atlantic. They tagged several adult female loggerhead sea turtles and large tiger sharks and tracked them by satellite to see where each group of animals went throughout the year. They found that in the summer the sharks moved closer to the sea turtles' nesting areas in the Carolinas, ready to feed.

Scientists believe that sea turtles swim to the surface of the water more often in summer partly because of increased metabolism and to navigate, explains a guide provided by the University of Miami.

According to the "landscape of fear" model, the theory that animals' migratory patterns would be affected by fear of being attacked by a predator, sea turtles would alter their surfacing behavior or move to another area when there are more sharks around. But the University of Miami researchers found no change in the sea turtles' movements or surfacing habits. The sharks were not so lackadaisical, and in fact, "exhibited modified surfacing behaviors that may enhance predation opportunity."

Neil Hammerschlag, a research assistant professor at UM's Rosensteil School, suggested that fishing for sharks may have reduced their population enough that they aren't a major decision-making factor for turtles, compared with problems like getting hit by boats. A study published in 2013 by researchers from Florida International University found that a global increase in shark fishing had culled their numbers by about 100 million in 2000 and 97 million in 2010. (Why should we care? PBS explains the dangers of a world without sharks.)

The researchers say these findings about the apparent indifference of sea turtles to increased shark presence could have "implications for evolutionary biology, community ecology and wildlife conservation."

They could also mean that the sea turtle has nerves of steel and should be the next honey badger, so get your memes ready.