Marine Science in the News: Cranky crabs have an edge in “claw to claw” combat

This week’s Marine Science in the News blog highlights a recent study about some of MSI’s favorite animals: hermit crabs!

These shelled arthropods carry their home on their back. The shell is more than just a home; it protects the crab’s soft abdomen, helps maintain a proper level of moisture and protects against predators. A good shell is a hot commodity in the hermit crab world! Sometimes a hermit crab will take a liking to a fellow hermit crab’s home, resulting in a “shell fight”.

According to research recently conducted by the Universidad Nacional Autónoma de México and Texas A&M University, crabs living in broken shells value an intact shell and will fight more aggressively to get a better one. The research team concluded that sheer aggression rather than pure muscle strength gave crabs the edge during a shell fight. Despite broken-shelled crabs having reduced metabolism, low energy levels and poor nutritional intake, they still outperform and outmaneuver hermit crabs with intact shells.

Click here to read a summary of the study and discover how aggression and desperation for a better shell give crabs the upper claw in a fight.

Journal reference:

Guillermina A. and G.I. Jofre. 2017. Aggressiveness compensates for low muscle strength and metabolic disadvantages in shell fighting: an outcome of the individual’s past. Behavioral Ecology and Sociobiology 7(6). DOI:10.1007/s00265-017-2311-7.

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