TOKYO - When a nearly 20-foot long tentacle was hauled aboard his research ship, Tsunemi Kubodera knew he had something big. Then it began sucking on his hands. But what came next excited him most - hundreds of photos of a purplish-red sea monster doing battle 3,000 feet deep.

It was a rare giant squid, a creature that until then had eluded observation in the wild.

Kubodera's team captured photos of the 26-foot-long beast attacking its bait, then struggling for more than four hours to get free. The squid pulled so hard on the line baited with shrimp that it severed one of its own tentacles.

"It was quite an experience to feel the still-functioning tentacle on my hand," Kubodera, a researcher with Japan's National Science Museum, told The Associated Press. "But the photos were even better."

For centuries giant squids, formally called Architeuthis, have been the stuff of legends, appearing in the myths of ancient Greece or attacking a submarine in Jules Verne's "20,000 Leagues Under the Sea." But they had never been seen in their natural habitat.

The Japanese team, capping a three-year effort, filmed the creature in September of last year, finding what one researcher called "the holy grail" of deep-sea animals.

The results were not announced until this week, when they were published in today's issue of the British journal, the Proceedings of the Royal Society B: Biological Sciences.

Giant squid are the world's largest invertebrates, having been known to exceed 50 feet. Kubodera said the one he caught on camera was probably an adult female. He said the squid's tentacle would not grow back, but its life was not in danger.

"That's getting footage of a real sea monster," said Randy Kochevar, a deep-sea biologist with the Monterey Bay Aquarium in California. "It's really an incredible accomplishment."

The photos - taken with strobe lights at 30-second intervals - also shed some new light on the animal's behavior.

"We think it is a much more active predator than was previously thought," Kubodera said today. "It had previously been seen as more lethargic and not as strong."