Voracious “red devil” squid are on the move.

It was like a scene from a grade-B horror film. On a gently rocking vessel in the warm waters of the Sea of Cortez, a young oceanographer earnestly watches her computer screen while colleagues lower a cable into the water.

Instruments aboard the ship, the Pacific Storm, ping sound waves toward the cable. The oceanographer’s eyes flicker across the screen to make sure the signal is clear. Tethered to the cable is a 5-pound Humboldt squid, and the sound waves, set at 38 kilohertz, bounce off the squid. An image shows up on the screen.

The oceanographer raises her fist in triumph. It marks the first time scientists had clearly picked up a strong sonar signal for squid, which lack the bones and swim bladders that give away other marine creatures.

Suddenly a second image appears, darting up from below. The acoustic signal tracks it from the depths toward the cable — and the tethered squid. It is another squid, larger than the first, and it attacks the tethered animal. The oceanographer screams.

Fade to black.

Read the rest of the story on Kelly Benoit-Bird and her research on squid in the Summer 2008 issue of Terra.