Plastic bags in the ocean can look just like a jellyfish or other gelatinous creature, fooling loggerhead turtles into hunting them.
This case of mistaken identity, documented in the latest issue of the journal PLoS ONE, reveals how our garbage can hurt marine wildlife. Even if a turtle doesn't ingest the bag, the effort to explore and grab it wastes the turtle's energy and time.
BLOG: How Turtles Got Their Shells
Tomoko Narazaki and colleagues from the University of Tokyo outfitted the loggerhead turtles with 3D loggers and crittercams, which enabled the scientists to record all of the turtle action as the animals swam in open water.
Narazaki and his team discovered that the turtles rely on sight, rather than on sound or smell, to find and move toward gelatinous prey, such as jellyfish and other organisms. That's bad news for the turtles, because a plastic bag looks just like a jellyfish when the bags are submerged in water.
That's hard to imagine, but the bags tend to lose their shape and take on a more tubular form when submerged. As they float downward in the water, the plastic undulates, making the bag look just like a living, moving jellyfish. I've seen this before myself, and the resemblance is uncanny.