Researchers at the University of Delaware wanted to determine how quickly the crabs decorated themselves, and if they did it with and without a place to hide. The experiment was fairly simple; have two separate containers, one with a habitat and one without a place to hide. Then, using wet craft pom-poms so that they would sink to the bottom of the container, the crabs were photographed every hour for 24 hours.
In both containers most of the crabs were decorated within 6 hours. All of the crabs were completely covered after 24 hours. The difference was in which part of their body they protected first. If a habitat was available, the crabs decorated their appendages first and the ones without a place to hide, decorated the entire body. Since the crabs do not have color vision they probably failed to recognize that they were celebrating a holiday. "Tis the season"!