BEIJING, June 29 (Xinhuanet) -- When it comes to catching squid, which have a keen sense of smell, very good eyesight, and can squirt dark ink to hide their escape, humans could learn a lot from whales -- but whales aren't talking.
"The numbers of squid that are eaten
by sperm whales far exceed those harvested by men for food on a worldwide
basis," said squid-expert Roger Hanlon of the Marine Biological Laboratory in
Woods Hole, Massachusetts.
But how whales manage to find
and devour skiddish squid remains a mystery. One hypothesis, proposed more
than 20 years ago, speculated the whales used powerful ultrasound shrieks to
knock their squid prey senseless before gulping them down. Like bats and
dolphins, some whales use ultrasonic clicks to find prey and
A new study by Hanlon and his
colleagues reveals squid cannot be paralyzed by whale ultrasound. In
fact, they are not even aware they are being targeted. The team's findings are
detailed in the July 7 issue of the journal Biology
The researchers played recorded
ultrasound whale clicks to several long-finned squid (Loligo pealeii) swimming
in a water tank. This species of squid grows to about a foot long and is
commonly found off the coast of the northeastern United
กก The ultrasound clicks were broadcast at up to 226
decibels, which is about the most intense whale echolocation click a squid would
be exposed to in the wild. Not only were the squid not knocked senseless, they
did not react at all to the ultrasound bursts, and actually swam in front of the
speaker as if nothing were happening.
"That's like a Bose commercial where
you're sitting there and your hair is straight back because the sound is
blasting out," Hanlon said. "That to us was a stunning result. We did the
experiment several times over because we could hardly believe it
So if whales don't use sound waves
to knock out squid, how do they catch them?
"Why can't [squids] see some aspects
of this big whale heading down on them at a zillion miles an hour? That's a big
mystery," Hanlon said.