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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.

The Marine Science Institute was founded in 1970 as a non-profit organization focused on stewardship for the natural environment of the San Francisco Bay Area. MSI delivers engaging and interactive marine adventures led by inspirational marine science educators. MSI has served more than a million students of all ages and economic backgrounds with a hands-on approach to fostering respect for the marine ecosystem from the Sacramento Delta to the Pacific Ocean. From San Francisco Bay voyages on the 90-foot R/V “Robert G. Brownlee,” to school visits by MSI’s traveling aquarium, to marine camps and family canoe trips around the Peninsula wetlands, MSI offers a wealth of ways to touch and feel the marine environment.

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