Hermit Crabs Are Increasingly Using Plastic Trash As Homes

Most crabs have strong exoskeletons to protect them from predators. However, hermit crabs are born with soft bodies. They have usually lived inside sea shells or old snail shells. But, a recent study by Polish scientists has found that the tiny crustaceans are increasingly turning to trash for refuge.

For their research, the team looked at hundreds of images of hermit crabs on social media. They found 386 examples of the crabs living inside artificial shells. Eighty-five percent were using plastic caps, while the rest chose metal or glass trash. This behavior was seen in 10 of the 16 species of land-dwelling hermit crabs, all the way from Africa to Central America.

"We confirm for the first time that the use of artificial materials by hermit crabs is a behavior occurring on a global scale," the researchers said.

The study was published in the journal Science of the Total Environment on February 25, 2024. It did not explore the potential harm of artificial shells to hermit crabs. However, a 2019 study found that over half a million hermit crabs on a remote Indian Ocean island die every year. They get trapped inside plastic items like bottles.

Researchers are unsure why hermit crabs are choosing artificial shells. But they have several theories. Some believe the crustaceans are struggling to find natural shells and are using whatever else they can find. Others think plastic may be a more attractive option because it is lighter and easier to carry. It may also provide better camouflage in an environment filled with trash.

"When I first saw these pictures, I felt it was heartbreaking," study co-author Marta Szulkin told The BBC. "But at the same time, I think we really need to understand that we're living in a different era, and animals are making use of what's available to them."

Resources: Smithsonian.org, WashingtonPost.com, NPR.org