Hermit crabs worldwide are increasingly using plastic waste as a substitute for shells, according to an analysis of photos taken by wildlife enthusiasts and shared online. Scientists have expressed distress at the extent to which the creatures are inhabiting human garbage. The study, published in the Science of the Total Environment journal, found that two-thirds of hermit crab species were pictured in “artificial shells” – items discarded by humans.
The research, led by urban ecologist Marta Szulkin from the University of Warsaw, used social media and photo-sharing websites to gather data. Szulkin and her colleagues observed 386 instances of crabs using artificial shells, primarily plastic caps. They found that this behavior was prevalent among ten out of the 16 species of land hermit crabs worldwide.
The impact of these materials on the crabs is yet to be determined. The study also raises questions about how this use of plastic might affect the evolution of these crustaceans. The crabs traditionally use discarded snail shells for protection, and often fight over them when in short supply. However, with natural shells declining, the availability of artificial alternatives could be increasing.
A recent study estimated that at least 171 trillion pieces of plastic are currently floating in our oceans, a figure that could nearly triple by 2040 if no action is taken. However, there is hope that a global treaty to end plastic pollution could be signed by 2024. Mark Miodownik, a professor at University College London, suggested that humans could learn from the hermit crabs’ reuse of plastic rather than discarding it.