What has two tentacles, eight arms, a beak, and eyes as big as hubcaps?
Answer: a giant squid, the sea creature of legend and reality.
Regular-sized squid are fairly common. They range in size from less than a foot to nearly 40 feet long. They're easily found in oceans worldwide. Squid are related to the octopus, cuttlefish, and nautilus - part of the cephalopod (SEF-uh-luh-pod) family.
It's the giant squid that is one of marine research's most confounding mysteries. That's because no one has ever seen a live one.
"It's tremendous. It's one of the largest creatures in the ocean," says James Bellingham of the Massachusetts Institute of Technology in Cambridge. He went on an expedition last year to find a giant squid. "There may be a huge number of them out there."
But if no one's ever seen one swimming around, how do we know they exist? Scientists have found the remains of giant squid in the stomachs of whales. And sometimes, giant squid are dredged up in fishing nets.
Sailors told of boat-swallowing monsters; strange creatures washed up on shore were thought to be mermen. Scientists researching those tales conclude that the stories described giant squid.
The mermen belief was widely held until 1854, when Japetus Steenstrup, a Danish cephalopod specialist, concluded that the "mermen" were really big squid.
Jules Verne's famous book "Twenty Thousand Leagues Under the Sea," written in 1861, was partly based on a reported encounter between a French naval ship and a giant squid.
Today, the shy, overgrown mollusks, which have no bones, still elude researchers' cameras. But we know giant squid are not the aggressive, boat-wrecking monsters of legend.
How "giant" is a giant squid?
Some fishermen claim to have encountered squid as long as 100 feet, from the tip of its tentacles to the end of the body. (The largest animal on earth - the blue whale - grows as long as 100 feet.) Scientists have found dead squid that were 60 feet long, and estimate they can grow to 75 feet. Whether they can be bigger than that has yet to be proved. (The illustration at right shows what a 75-foot-long squid might look like.)
With all the technology now available - scuba gear, sonar, submarines, and underwater robots - it's hard to imagine how a creature as large as the giant squid has escaped discovery.
It might be because there's still so much ocean to explore, Dr. Bellingham says.
"It's a really minuscule amount of time we spend in the ocean," he says. "And the giant squid tend to live in depths of the ocean we go to infrequently."
The squid probably live in the oceans' middle depths - not near the surface, and not on the ocean floor. Surface ships would spot the squid if they lived nearer the surface. And researchers are more likely to visit the ocean floor.
Also, giant squid are a popular snack for sperm whales. To survive, squid have to be good hiders.
Last year, Bellingham and other scientists set out to find the giant squid. They chose to scout the underwater Kaikoura Canyon, off the coast of New Zealand. It's a popular feeding ground for sperm whales. Giant squid have been caught in fishing nets there, too.
Using an underwater robot (they called it an "autonomous underwater vehicle," or AUV), the scientists searched about half a mile deep.
Every morning for three weeks they took their eight-foot-long, camera-equipped AUV aboard a fishing boat. They would head for areas where sperm whales had been hunting. Then they would lower the robot to take a look.
They found lots of marine life - whales, eels, sharks, and all sorts of fantastic fish - but no giant squid. They didn't even catch a glimpse of one.
Bellingham and his crew weren't discouraged, though.
"We haven't discovered everything about the ocean," he says. "We really don't know what's out there. What else might be out there we don't know about? It's fantastically exciting."
Scientists have pieced together a lot about the giant squid based on the specimens they've found and on what they know about smaller squid. But there are lots of questions they can answer only by observing a living giant squid. What do they eat? How fast do they grow? Do they live alone, or in groups?
Scientists are sure about one thing: The giant squid holds the record for the largest eye of any known animal.
Giant squid aren't the only legendmaking - and real - creatures in the ocean depths.
Scientists are continually discovering new species and learning more about creatures they already knew existed.
Jason Cressey of POD (People, Oceans, Dolphins) in Vancouver, British Columbia, reports that a new species of dolphin was recently discovered in New Zealand. It doesn't even have a name yet.
Scientists also recently found that the bottle-nosed whale is the world's deepest diver. It can go two miles straight down, Dr. Cressey says.
Perhaps you've gone on a whale watch and seen humpback whales. They're fairly common. But did you know that each male humpback sings a song unique to it? And each year, they add another 10 minutes to their personal songs. It's like they write a new verse every year!
BOTH Bellingham and Cressey emphasize that there's lot more to discover in the ocean.
Cressey says that whenever a new whale or dolphin is spotted, it's usually by a dorsal fin or the tail. He compares that brief glance to what we know of the ocean. "That's really all we know - just the back, the tip."
"We have better maps of the back side of the moon than we do of the ocean," Bellingham says.
* For more information on the search for giant squid, try this Web site: