Imagine coming face to face with a cannibalistic creature that is as tall as you are and has long tentacles, a razor-sharp beak, and skin that flashes with bizarre, dazzling color. NATURE’s Encountering Sea Monsters does just that, as underwater cameraman Bob Cranston explores the remarkable world of marine creatures called cephalopods. Cephalopods include squids, cuttlefish, octopi, and nautili.

Cranston and top marine scientists dive in waters from Indonesia and Mexico to Australia and Texas, meeting up with a variety of cephalopods — from the tiny but deadly blue-ringed octopus to the giant Humboldt squid, known for its aggressive behavior, flashing light shows, and cannibalism.

Join Bob Cranston as he fearlessly reaches out and interacts with some of the ocean’s most fascinating life forms.

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Online content for Encountering Sea Monsters was originally posted December 2005.

There is one less mystery in the deep sea: two Japanese researchers have finally photographed a live giant squid. It’s the first time one of the world’s largest cephalopods has been documented in its ocean home.

“It is just a sensational accomplishment,” says Dr. Mark Norman, a leading squid expert who appears in NATURE’s Encountering Sea Monsters.

The giant squid has long been the stuff of legend. Mariners claimed it sank ships and plucked sailors off decks. Even scientists admit it is a very mysterious creature. Dead specimens periodically wash up on beaches, but no researchers had ever seen one alive until recently.

First image of a live giant squid, known as Architeuthis.

Over the last decade, there’s been a race to change that. Some scientists have descended in submarines, hoping to catch a glimpse of one of the several known species of giant squid, which are believed to live in deep water, a thousand feet down or more, in oceans around the globe. Others have dragged camera-laden sleds across the ocean floor, hoping to take a portrait of one of these monsters, which are believed to grow up to 40 feet long.

Two Japanese researchers, Tsunemi Kubodera of Tokyo’s National Science Museum and Kyoichi Mori of the Ogasawara Whale Watching Association, had a different idea. First, they identified an area where fishing boat captains and tourists had seen sperm whales with sucker marks on their skin, indicating a confrontation with the giant squid. They rode out to the spot on a Japanese fishing boat. Then, they lowered a hook baited with a single small squid, nearly 3,000 feet down. Also attached to the line: an automated digital camera that snapped a picture every few minutes.

The two squid hunters had little luck for years. Then, on September 30, 2004, in the waters off Japan’s Ogasawara Islands, they succeeded. A squid about 25 feet long rose from the depths and took the bait. One of its arms got snagged on the hook. For more than four hours, it struggled to get free. Finally, the snagged tentacle broke off. By the time it was all over, the camera had snapped more than 500 pictures of the squid, which scientists call Architeuthis. When they pulled up the camera, the researchers retrieved the 5-foot-long tentacle tip as a souvenir. When Mori took it off the hook, he later told reporters, it was still moving. Its suckers even stuck on to the deck.

Architeuthis’ severed tentacle

The researchers studied their photos for more than a year, then publicly released them in a scientific journal in late 2005. The team explains that the photos show the squid hovering, “flying” through the water, and aggressively wrapping its tentacles around the bait. That suggests Architeuthis is “a much more active predator than previously suspected,” perhaps used to chasing and tracking down prey rather than waiting in ambush.

The Japanese researchers “were extremely clever on every level,” says Dr. Norman, a senior curator at Museum Victoria in Australia. “My guess is that everyone is going to be breaking down their door and asking for help over the next few years.” He says the next step will be to get moving pictures of this and several other species of giant squid that live deep in the ocean.

They told him not to go. They told him the animals were dangerous and unpredictable. Diving at night so far offshore was also risky. But did Bob Cranston listen?

The expert underwater cameraman decided to wave off advice from local fishermen along the coast of Mexico and as a result, NATURE’s Encountering Sea Monsters includes some of the most memorable footage ever captured of the giant Humboldt squid.

“It was some pretty hairy diving at times, but it was fascinating and well worth it,” Cranston recalls.

Cranston, a veteran of filming sharks and other dangerous sea creatures, had come to the Sea of Cortez to document an animal locals call “the red devil.” In part, that’s because the Humboldt, which can reach 6 feet long and weigh up to 100 pounds, often has devilishly red skin. But the nickname is also due to the squid’s habit of hunting at night and its notoriously aggressive behavior. Schools of Humboldts have been known to test divers with their sticky tentacles and sharp beak, and blast fishermen with jets of water and purple-black ink. They have also been known to eat each other.

The photographer was aware of the Humboldt’s reputation. Several years ago, Cranston had his first encounter with this cephalopod after following local squid boats out to their nighttime fishing grounds. The fishermen use bright lanterns to lure squid to the surface, then catch them on baited hooks or snare them with specialized spears. Cranston was warned not to swim with the fearsome animals: “Some fishermen [said] the squid literally pulled men into the sea and ate them.”

Cranston dove in anyway, and was soon surrounded by the speedy, powerful animals. A mature Humboldt “can pull you around quite a bit,” Cranston says. “They’ll come up to you and kind of grab hold with their tentacles, test your strength, pull you down, kind of take a little taste. They are very inquisitive. If you resist, they’ll back off. But it is very exciting.”

This encounter made Cranston even more curious about the Humboldt. He became fascinated by the behavior of cephalopods which have special skin cells that allow it to produce a dazzling array of colors. Scientists believe the light shows are used for communication and courtship, but are not exactly sure how. While filming Encountering Sea Monsters, Cranston decided to do a little research of his own.

Cranston wanted to see if filtering his camera lights might make Humboldt squids easier to film. “We use 650 watt lights that are very bright, and this is a nocturnal animal that lives in the deep, dark ocean, so they don’t seem to like them very much. We put some red filters on, assuming that it is a color you don’t see in the deep ocean. And yes, it worked: the squid came in closer.”

Cranston also looked for a way to mimic the flashing colors the squids use to communicate. The solution? A special strobe light that looks like a light saber. “It was a creative approach,” he says.

The experiment produced a memorable moment, recorded on film. As Cranston dives 150 feet down, a curious squid suddenly rises up from deep water and, for a moment, the two make contact in the pulsing light.

“They may seem like aliens to us,” remarks Cranston, “but cephalopods are simply remarkable organisms. They are smart, clever, sophisticated. And there is such a wide variety — from little pajama squids that have tremendous personality to cuttlefish that build [and care for their] nests.”

Cranston is looking forward to capturing more tentacles with his camera. “We’re finding new kinds of cephalopods all the time,” he says, noting that researchers have identified dozens of new species in just the last few years. “So there is always something new and interesting to see.”