Invisible squid

Science News spreads the news of an underwater arms race. Sonar specialist T. Aran Mooney of Woods Hole has discovered that squid are invisible to sonar underwater:

…[B]y putting a longfin squid through a CT scanner while testing squid hearing, [they found the] squid’s body blended into the tub water around it, meaning that squid do not reflect sound well.

They’re hunted by dolphins, who use echolocation to find them.