Rare footage of a giant squid has been captured by divers off the coast of Japan. Yosuke Tanaka and his partner Miki, who run a scuba diving business, saw the animal swimming near the surface of the water. 

"I was so excited," Yosuke told Newsweek. "And I felt terrified because it had very thick arms – if I was caught, I would not be able to escape."

Giant squid (Architeuthis dux) are one of the world’s most mysterious species. Most of the information known about this species has come from dead specimens that have washed up on the world’s beaches. These specimens can only tell us so much as they are often damaged and missing tentacles, which makes this footage all the more interesting. 

Unfortunately, as can be seen in the video, the giant squid was moving slowly and had damaged pieces of its skin peeling from its body. There’s some suggestion the squid is exhibiting unusual behavior by being near the water's surface as these squid are thought to live at depths of 300 to 1,000 meters (985 to 3,280 feet). 

This squid was thought to be around 2.5 meters (8 feet) long, which would make a relatively small specimen, as the largest ever squid on record had a total length of almost 13 meters (43 feet). 

Squid have eight arms and two tentacles used for locomotion and prey capture. By studying the stomach contents of these specimens, researchers have found that giant squid likely eat fish, shrimp and other squid. There’s even evidence to suggest that the larger squid would eat small whales. 

Along with their cousins the colossal squid (Mesonychoteuthis hamiltoni), they have the largest eyes in the animal kingdom that can measure 27 centimeters (11 inches) across. This is thought to be an adaptation to living the dark depths of the ocean and could help them spot predators like sperm whales. 

"I have heard not a lot is known about this creature. I'd be happy if this helps us learn more," Tanaka told AFP.