After fueling myth and nightmare for more than two millennia, one of the ocean's biggest mysteries is finally yielding a few of its secrets to science — and rolling into Seattle.

Within the past several years, researchers have, for the first time, photographed a giant squid in its natural habitat, captured live young and hauled a writhing specimen onto the deck of a ship.

"Absolutely marvelous discoveries," says Clyde Roper, with no hint of envy in his voice.

Roper, a researcher for the Smithsonian Institution, has been chasing the giant squid for more than four decades — and he hasn't caught it yet. But his studies of more than 50 carcasses washed up on beaches and snagged in fishing nets have been pivotal in piecing together what little is known about the world's largest invertebrate.

He also was the force behind a traveling Smithsonian exhibit that opens today at the University of Washington's Burke Museum of Natural History and Culture.

"We really want folks to understand and appreciate giant squid and not think of them as monsters," he says.

It's not surprising medieval sailors had a less benign view of the behemoths. Some of the earliest recorded specimens stretched nearly 60 feet from head to tentacle tip. Sperm whales sometimes burst to the surface entangled in tentacles, leading artists to depict epic battles between the two denizens of the deep.

In reality, no one could have witnessed such a life-and-death struggle, though sperm whales love to feast on giant squid. The squid, with the scientific name Architeuthis, are adapted to the deep ocean, Roper says. "They cannot live very long at the surface."

Indeed, the small female hooked and filmed by Japanese scientists last December survived only briefly after being yanked up from a depth of nearly a half-mile.

Two years before, the same scientists were the first to photograph a giant squid in the wild. They mounted a camera on a line, lowered it 3,000 feet into the North Pacific and snapped pictures that show a ghostlike squid nearly 30 feet long attacking a baited hook.

The New Zealand researcher who netted the baby squid found them at shallow depths but was not able to keep the 2-inch-long larvae alive.

Nothing comes easy in giant-squid research, Roper says. The Japanese team mounted several voyages before its first giant-squid sighting.

But the number of dead giant squid turning up in fishing nets has boomed in recent years, as fleets pursue deeper-water species such as orange roughy, a favored food of the creatures. Those giant-squid specimens have debunked some earlier notions, including the assumption that the species must be long-lived because they are so large. (Males average about 20 feet and females just under 40 feet.)

But when Roper examined their reproductive organs, he concluded the animals grow fast, probably breed only once and live at most three years.

"They must be absolute eating machines," he says.

The squid snag their prey with long feeding tentacles and shovel it into a mouth equipped with a hard beak, like a parrot's.

Giant squid appear to live in all major oceans, Roper said. Several have washed up on the West Coast of North America, from Baja California to the Pacific Northwest.

The Smithsonian's traveling exhibit does not include a preserved specimen, said Ron Eng, collections manager for The Burke. But it does feature suckers and beaks, along with film clips and displays — including one that shows the eye of a giant squid is as big as a human head.

The exhibit also points out that there are other huge squid in the sea. The colossal squid, found in Antarctica, may rival the giant squid in size. Humboldt squid, which have turned up in recent years off California, Oregon and Washington, grow up to 6 feet long, hunt in packs and have been known to attack divers.

Roper, who has studied several squid species, finds them all fascinating. But he's still holding out hope someone will come face-to-face with a big one on its home turf.

"I really do believe it will happen one of these days," he says. "I'd like to think it will be when I'm sitting in a submersible."

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com