There are many theories as to why sea turtles or other animals ingest plastic. Some have speculated that turtles mistake plastic for food because of their appearance and flow; For example, when a turtle eats a plastic bag that looks like a jellyfish. Sea turtles around the world have been eating plastic for years, but scientists are not sure why; until now

Scientists at the University of North Carolina at Chapel Hill conducted a study, published in Current Biology, on how turtles might be attracted to the smell of plastic. They present captive sea turtles with many different scents and discovered that plastic bags smell like a tasty treat to turtles, due to bacteria and algae that accumulate on their surface.

Kenneth J. Lohmann, UNC-Chapel Hill biologist, said:

This finding is important because it is the first demonstration that oceanic odor plastics make animals eat them. It is common to find loggerhead turtles with their digestive systems totally or partially blocked because they are used to eat plastic materials.

The team held 15 loggerhead turtle hats for five months as they delivered a series of odors into the air through a pipe. The turtles ignored the smells of clean water and plastic, but responded to the smell of ocean-soaked plastics and food sticking out of their tiny noses into the water. When turtles smelled of biofuel plastic, they stuck their noses out to smell three more times, just as they responded to real food. Biofuel plastic is a plastic that has been deposited in water long enough to accumulate microbes, algae, plants, and small animals on its surface.

Hungry sea turtles eat plastic because it smells like food
A young loggerhead turtle swims in an experimental tank. Photo Credit: UNC-Chapel Hill Lab

This study reveals how an increasing amount of plastic debris is life-threatening to turtles and other marine animals, including seabirds, fish, and even whales.

The researchers estimate that more than 50% of the world’s sea turtles, and almost all seabirds, have ingested plastic. This is not surprising, as more than 8 million tons of plastic are dumped into the oceans each year.

Previous research has shown that consuming just 14 pieces of plastic can kill turtles. Young turtles are particularly vulnerable because they like to swim in currents where a significant amount of plastic debris accumulates. Once a turtle ingests the plastic, it cannot throw it away again. As a result, the consumed plastic becomes clogged in the turtle’s intestine and limits its ability to digest and absorb food.

Joseph Pfaller, co-author of the study, explained:

The plastic problem in the ocean is more complicated than the plastic bags that look like jellyfish or the wandering straw trapped in a turtle’s nose. These are important and troublesome puzzle pieces, and all plastics pose a danger to turtles.

Matthew Savoca, author of one of the study studies, believes this issue is a concern not only for sea turtles but also for other animals. “Previous research suggests that seabirds and some species of fish may also be tricked by their instincts to eat plastic,” said Savoca.

When sea turtles fill their stomachs with plastic, their bodies are fooled and think they are full, causing them to starve. In other cases, harder, sharper pieces of plastic puncture the turtles when they try to swallow them, or end up trapped in their throats and drown to death.

However, there are two simple solutions: reduce plastic consumption and recycling.