Researchers Shed Light on Mysterious Jumbo Squid

Stefan Lovgren
for National Geographic News
July 18, 2003

Ultimate Explorer: Devils of the Deep
Sunday, July 20, 2003 at 8 p.m. ET/PT on MSNBC

Elusive and cannibalistic, the Humboldt, or jumbo, squid (Dosidicus gigas) has a reputation so fearsome that it has earned the nickname "red devil." But to William Gilly, a biology professor at Stanford University in Palo Alto, the mysterious squid, which can reach six feet (1.8 meters) long, is a beautiful sea creature that provides important ecological clues.

Gilly has studied the behavior and biology of the Humboldt squid for more than two decades, tagging them in the Gulf of California as part of a larger study of their movements in the Pacific Ocean.

"This species is an important part of the ecosystems, both as a major predator and prey for even larger pelagic predators such as sperm whales," said Gilly.

"It's also the target of major commercial fisheries, not only in the Gulf but also off Central and South America. With so much unknown about the biology of this squid, it is impossible to intelligently manage such fisheries."

National Geographic Ultimate Explorer television correspondent Mireya Mayor recently followed Gilly and cameraman Bob Cranston on one of their expeditions to Guaymas, Mexico, for the documentary Devils of the Deep, which airs this Sunday on MSNBC.

Tearing Through Flesh

Known as aggressive predators, Humboldt squid have powerful arms and tentacles, excellent underwater vision and a razor-sharp beak that easily tears through the flesh of their prey. They can also rapidly change their skin color in what appears to be a complex communication system.

"I was impressed by their sheer size," said Mayor. "They're absolutely beautiful. When they light up and change colors, it's like a spectacular underwater light show."

The color-changing behavior is controlled by the squid's brain and provides visual signals, but the purpose of those signals is still unknown. Indeed the creatures' habits are mostly a mystery to scientists.

Humboldt squid don't survive more than a few days in captivity, and studying their behavior in the field is hard without interfering with them.

"We know so little because they spend 95 percent of their lives at depths well beyond those safely observed with scuba," said Gilly. "We don't know where they spawn, and their eggs have never been found in the wild."

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