BEIJING, Feb. 28 (Xinhuanet) -- It's a fast, aggressive predator that swims
backward and forward, flashes light at its prey before attacking and has eight
arms. What is it? A deep-sea eight-armed squid.
Zoologist Tsunemi Kubodera at Japan's National Science Museum in Tokyo and
his colleagues are the same researchers who caught the first live giant squid
(Architeuthis) footage two years ago. They recorded the deep-sea eight-armed
squid Taningia danae for the first time using a newly developed underwater
high-definition video camera system.
The first live videos of the creature showed it swimming forward and
backward around bait, attacking a rig line on which researchers dangled
bait, flashing light at prey, potentially to blind it, and attacking the halogen
light researchers used to observe it.
"Blue light seemed provocative," the researchers wrote in their online
report in the Feb. 13 issue of the journal Proceedings of the Royal Society
B.
The researchers also saw the squids emit short bright light flashes from
large glowing organs at the tips of their tentacles before their final assaults.
Kubodera and his colleagues speculate these flashes might blind prey or help the
squids measure distance to their targets in the dark depths of the sea.
As the squids wandered around the red flashlights attached to the bait rig,
the scientists also saw the animals pulse long and short glows. These might be
attempts at communication or even "potential courtship behaviors," Kubodera and
his colleagues wrote.
The deep-sea eight-armed squid is the largest known bioluminescent or
light-emitting creature in the world. The largest known specimen grows up to
7.5-feet long and 130 lbs., with eyes the size of large grapefruits. Hundreds of
their beaks have been found in sperm whale stomachs, suggesting these are very
abundant in tropical and subtropical oceans.
The researchers tracked the squid off the Ogasawara Islands, roughly 600
miles south of Tokyo. They suspended their cameras from about 750 to 3,000 feet
deep, and on a pole attached to the cameras, Kubodera and his colleagues dangled
tiny flashlights and bait, either a smaller squid or a mackerel.
The squid naturally possesses many tiny cavities of ammonia solution within
its flesh to help maintain buoyancy, making the bodies of captured specimens
flabby and soft to the touch. This led scientists to suspect it moved
sluggishly.
However, the new videos reveal the squid is far from sluggish. T. danae can
flap its large, muscular, triangular fins to swim both forward and backward and
is highly maneuverable, rapidly changing direction by bending its flexible
body.
(Agencies)