Science: The Squid's Stratagem

Squids, say the natural history books, use their ink to form clouds that blind pursuers. Not so, says D.N.F. Hall of the Singapore Regional Fisheries Research Station, writing in Nature. Squids are more subtle than that.

Hall began to doubt the cloud theory when he watched squids discharging their ink. It does not form a cloud for a considerable time, but hangs together as a dark, viscous mass. To learn more, Hall experimented with a small captive squid in a light-colored wooden tub. When his hand approached it, the squid changed color rapidly, as squids do. Just before Hall grabbed for it,...