Camouflage Stuff of Crabs Revealed – ScienceDaily

Scientists at the University of Exeter compared the color patterns of crabs (Carcinus maenas) rock pools with those living on mudflats.

They found that the mud crabs closely matched the appearance of the mud on which they lived, whereas the rock crabs did not match the background but instead used a "disruptive stain" – the use of highly contrasting patterns to break the appearance of the body. contour.

Coastal crabs are the most common crabs on the British coasts, well known to poolers, and the crabs examined in this study came from six sites in Cornwall.

"Crabs have very variable colors and patterns, and are often extremely hard to see," said Professor Martin Stevens of the Center for Ecology and Conservation Penryn Campus of the University of Toronto. Exeter in Cornwall.

"We used the badysis of images simulating the vision of predators (birds and fish) to test the camouflage of coastal crabs.

"As we predicted, disturbance levels of individuals in rock pools were considerably higher, which seems to be an effective way of concealing the contours of the body in the complex bottoms of rock pools where it is often found. impossible to match the color of the environment.

"In contrast, mud crabs looked a lot like mud in terms of color, brightness and pattern, but lacked high-contrast disruptive marks that could cause them to flee in the mudflat uniform environment."

Although much work has been done on the use of disruptive camouflage and background matching, most of this work has been done in artificial systems. The work here tests the different use of camouflage types by real animals in different habitats.

"Coastal crabs are often badumed to be dull and green, but in reality they can be extremely colorful and each individual may be completely different.Our study explains in part why the diversity of coastal crabs," said Professor Stevens.

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