Crab hats!

The sponge crab, one of our favourites at Crab Museum is famous for the way it adorns its head. It snips off pieces of coral sponge which is often poisonous and sticks it to the rough surface of its exoskeleton.

Researchers from the Shirahama Aquarium and Kyoto University, studied these crabs and their hat wearing in depth. They used plastic sponges and observed the crabs as they decided on the sponge.

The crabs spent on average 50 minutes deciding on the sponge to use, and up to 5 hours meticulously pinching off chunks to make a hole so that they could fit themselves inside.

Each crab had a slightly different way of creating their hats and hat making was exclusively observed at night-time - presumably when there was less threat from predators.

The biggest crabs however didn’t bother making hats at all - the researchers suggest that the effort making a hat wasn’t worth the defensive properties.

While the researchers did not come to any conclusions regarding crabs and 18th century fashion, their work shines light on how crabs think.

Future research will focus on crabs preferences for different sponge types, and hopefully help us understand this amazing behaviour!