Sperm whale feasting on a giant squid (rare images)
They are creatures of the deep immortalised in fictional bestsellers like Herman Melville's novel Moby Dick and Jules Verne's 20,000 Leagues Under the Sea.
But these ultra-rare images of a colossal sperm whale feeding on a giant squid are the real thing.
The captivating pictures show adult sperm whales feasting on a rare giant squid. Though the squid looks small beside the enormous whales, it is thought to be an incredible eight to ten metres long.
One of the dead squid's tentacles - a leftover scrap - was measured at a jaw-dropping three-and-a-half metres long.
And experts now think the pictures could be some of the rarest ever captured beneath the ocean's surface, showing as they do the sight of five adults teaching a hungry calf how to catch its prey.
Underwater photographer Tony Wu witnessed the pod - five adults and a juvenile - devour the mammoth squid near the Ogasawara Islands in Japan earlier this month.
'It was a childhood dream come true,' said Mr Wu.
'I remember reading Moby Dick and the kraken scene from 20,000 Leagues Under the Sea, dreaming about what it would be like to see a sperm whale eating a massive squid in real life.
'Of course, in reality the animals are not quite so ridiculously over-sized, but it was an adrenaline-inducing sight to witness.'
Sperm whales are the largest toothed whales in the world, inhabiting every ocean on the planet.
Researchers estimate that more than 110 million tons of squid may be consumed by the species every year.
However with feeding depths ranging beyond 800 metres deep, this behaviour has rarely been recorded.
On this once-in-a-lifetime occasion Mr Wu was lucky enough to see the adult whales appearing near the surface - and teach their calf to dive into the deep blue waters to feed on its prey.
'This is extremely rare,' said the 42-year-old.
'I had seen one video with sperm whales feeding on giant squid but I am not aware of anyone else who has documented this behaviour.
'Of course, I did not see the whale catch the squid at depth. I only saw the whale at the surface with the squid in its mouth. They brought it up from the depths.'
Accompanied by underwater photographers Eric Cheng and Douglas Seifert, Mr Wu entered the water to photograph the animals with permission from local whale watching authorities.
'The group kept diving and resurfacing with the larger whale carrying the squid in its mouth,' he said. 'They kept repeating the scenario and it was a good opportunity to get them on film.
'It seemed as if the adult whales were trying to teach the baby to dive and also to eat squid.
'Female sperm whales are known to raise calfs in a collective manner and they have strong family units.'
Cephalopod expert Dr Mark Norman confirmed the images give a rare insight into the feeding ritual of the sperm whale.
'It is incredibly rare to record a sperm whale with a giant squid actually in its jaws,' said Dr Norman, Senior Curator at the Museum Victoria, Australia.
'The region is famous for sperm whale aggregations and their regular dives to depth in this canyon system.
'I know of one previous record of a whale returning to the surface with squid remains in its mouth.
'This is the site where Dr Tsunemi Kubodera of the Tokyo National Science Museum deployed a baited still camera at 800 metres and got the only live animal shots of giant squid in its natural environment.
'The potential matrilineal teaching of calves is a wonderful thing to think of.'
And Dr Norman thinks the group may have been teaching the youngster to use its built in sonar - echolocation - to find food at depth.
'As echolocation is pivotal for sperm whales finding their prey, it is not out of the question that the females would release the dead squid at depth and let the calf echolocate and recognise it in the dark deep water, typically around 800 m deep.'
For Mr Wu, whose work has taken him from Papua New Guinea to Colombia and Costa Rica, the encounter was a once in lifetime experience.
'It is something that only a handful of people have ever seen,' he says.
'I've experienced unique connections with many of the subjects I photograph, from the smallest of fish to the largest of cetaceans, so I consider myself extremely fortunate.
'There's always a risk in trying new things, going places that aren't well explored, working with animals that aren't well understood. But the rewards can be spectacular.'Daily Mail