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Why might otherwise intelligent seabirds be chowing down on plastic trash as if it were a delicious feast? It’s hard to say, but a new study published in Science Advances suggests that the fact that the way some trash smells actually mirrors dying algae and other similar scents.
It might sound bizarre, but these birds are putting themselves in harm’s way by eating these poisonous plastics because they simply smell appetizing. What makes this strange is the fact that, until around the mid-20th century, Popular Science explains, researchers weren’t actually sure that birds could smell.
Of course, right now we all know better, and according to Matthew Savoca, lead author of the research paper in Science Advances, seabirds need a good sense of smell above all else because they get their food from the ocean and other large expanses.
“In other words, they are looking for a needle in a haystack,” Savoca explained.
So the fact that plastic rubbish smells like algae and other similarly appetizing grub for seabirds makes sense, especially the idea that they’d zero in on the first item that smells even remotely delicious if they haven’t eaten for a while.
“Tube-nosed seabirds use their incredible sense of smell to locate areas to feed well before they can see them. Our work does not disprove that plastic might also look like food to some marine animals that eat it,” Savoca explained. “Quite the opposite in fact, if plastic looks and smells like food it is probably more likely to be confused with food than if it just looked like food. The way the plastic appears visually, from the organism’s perspective (not what it looks like to us) is important to consider.”
The smell that’s given off, in fact, is a chemical compound called dimethyl sulfide (DMS.) It’s one of the main chemical signals that’s given off by algae, so it ends up smelling a whole lot like the same kind of trash the birds would actually eat. It’s not great news, of course, because the plastic debris isn’t good for the poor creatures, but at least we know why they gobble it up like it’s going out of style now.