ScienceShot: Hiding in Plain Sight

If you're trying to blend in, it pays to hang out with friends. Scientists and hunters have long known that animals or people that are camouflaged often go undetected if they remain perfectly still, but once they move they "break camouflage" and are quickly spotted. A new study shows, however, that camouflage remains partially effective if the moving target is part of a group of similarly patterned objects. In computer-based lab tests, researchers measured how long it took for test subjects to detect a camouflage-patterned ellipse when it was moving amid groups of similarly patterned circles—a test akin to a predator picking out a specific target from a group, such as a young zebra from its herd, or a wounded fish from its school (image). Although camouflage never prevented a subject from finding and identifying the target, it did substantially delay the process. And, the larger the group, the more time it took the subject to find and identify the elliptical target. Subjects took, on average, about 40% longer to find the elliptical target among five moving circles than they did to find it among 10 moving targets, the team reports online today in the Proceedings of the Royal Society B. The most effective camouflage patterns—those in which the pattern of the target matched that of its background, or those in which the pattern visually disrupted the shape of the object—slowed the identification process by 70%, a delay that in real life would be sufficient to boost a potential victim's chance to escape a predator.

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