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In Brief

Spooky Crabs Darken Camouflage From Day to Night

Horned ghost crab camouflage
Horned ghost crabs change their camouflage from day to night. (Image credit: Martin Stevens)

Some teenagers like to stand out with wild hairstyles and flashy clothes, but young horned ghost crabs prefer to blend into the background.

Juvenile crabs mimic daily changes in their environment, shifting their coloring from day to night, new research suggests. When the sun's bright at noon, the crab's light carapace matches the yellow beach sand in their Singapore habitat. At night, the crabs are darker, to better blend in with the shadows, lead study author Martin Stevens of Exeter University told the BBC.

Stevens noted the crabs react to the daily wax and wan of sunlight, not to shifting shadows, because a dark crab scuttling from a cave during the day would make easy pickings for predators. Only juvenile crabs shift their camouflage so dramatically, Stevens said. The study appears in the April 2 issue of the Biological Journal of the Linnean Society.

Read more: Martin Stevens' research group

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Becky Oskin
Becky Oskin covers Earth science, climate change and space, as well as general science topics. Becky was a science reporter at Live Science and The Pasadena Star-News; she has freelanced for New Scientist and the American Institute of Physics. She earned a master's degree in geology from Caltech, a bachelor's degree from Washington State University, and a graduate certificate in science writing from the University of California, Santa Cruz.