( CNN ) -- The first ever video footage of a giant squid swimming in the ocean depths is `` an enormous breakthrough , '' according to a prominent marine conservationist who wrote a book about the quest to find the mysterious creatures . `` People have been searching for them for hundreds of years , literally , '' said Richard Ellis , the author of `` The Search for the Giant Squid : The Biology and Mythology of the World 's Most Elusive Sea Creature . '' Scientists and television broadcasters released images this week of the 10-foot-long giant squid they had filmed deep in the Pacific Ocean , far off the coast of the Japanese mainland , during hundreds of hours of underwater research . The discovery is significant for both science and mythology , in which giant squids have long played a notable role , Ellis said in an interview on CNN . `` We 're going to learn how this thing moves , '' he said . `` How it swims , what it does with its arms when it swims . '' He described the squid as having eight arms and `` two very , very long tentacles which it uses to grasp its prey . '' Its limbs have suckers lined with sharp teeth . Monsters reminiscent of giant squids have been featured in fables and imagery through the ages , like the Kraken in Norse legend and the Scylla in Greek mythology . `` For a long time , people did n't even think they existed , '' Ellis said . The carcasses of dead giant squid that washed ashore eventually proved that the creatures were real , but finding live ones in the wild has proved extremely challenging . The first still photographs of one of the huge creatures were captured in 2004 , and footage was taken of one floating on the surface of the water in 2006 . But researchers and cameramen had never before managed to catch a glimpse of them in the ocean abyss where they live . The mission that finally tracked down the creature involved 55 dives in two special submersible vehicles that spent a total of more than 285 hours far beneath the waves . Some of the dives went deeper than 3,000 feet . The team of scientists and filmmakers on the mission came from a variety of institutions , including the National Science Museum of Japan , the Discovery Channel and the Japanese broadcaster NHK . They used equipment including `` ultra-sensitive camera systems with light invisible to squid , bio luminescent lures and secret squid attractants , '' the Discovery Channel said . NHK and the Discovery Channel say they plan to air their programs about the squid sighting this month .
The 10-foot-long giant squid was caught on tape deep in the Pacific Ocean . The creatures had never before been filmed in their natural habitat . The discovery is significant for science and mythology , a marine expert says .