Sea turtles became the face of the plastic pollution crisis when a video of a turtle with a plastic straw stuck up its nose went viral in 2015.

Now, researchers have discovered one reason why ocean plastic is so dangerous for turtles: To them, it smells like food. "This 'olfactory trap' might help explain why sea turtles ingest and become entangled in plastic so frequently," Joseph Pfaller of the University of Florida, Gainesville told Cell Press, as published by ScienceDaily. Indeed, one 2018 study found that 100 percent of turtles surveyed in the Atlantic, Pacific and Mediterranean had plastics in their stomachs. While most people have assumed that turtles were drawn to plastics because they looked like prey, such as jellyfish, Pfaller and his team realized that so far no one had really investigated how plastics smelled.

So the researchers studied 15 captive loggerhead turtles and piped different scents into their habitat: clean plastic, ionized water, their usual food and plastics coated with microbes, algae, plants and animals, as they are in the ocean. They then observed how long the turtles spent with their nares out of the water and how many breaths they took as indications of their attraction to the different smells. The results, published in Current Biology Monday, surprised the researchers: The turtles showed "indistinguishable" interest in their food and the ocean-like plastic. In both cases, the turtles kept their nares up three times longer than they did in response to the water and control plastics.