Picture a young sea lion — let's call him Joey — taking an afternoon swim along the coast of Alaska and coming upon a long, shiny plastic loop.

Of course, Joey doesn't know the loop is plastic. All he knows is that he's never seen something like this wriggling through the water before, and he'd love to play with it.  

"Sea lions are curious and playful creatures by nature," explains Sue Goodglick, a wildlife biologist with the Alaska Department of Fish and Game program that studies and tracks Steller sea lions like Joey. So, she says, when they come across plastic objects like this, they usually like to play with it.