American scientists filmed military dolphins surprising hunt in the Pacific Ocean

Using cameras strapped to the dolphins' backs, scientists captured point-of-view footage of dolphins hunting live fish in the Pacific Ocean in an attempt to answer questions on how the animals feed.

The six dolphins involved are owned by the US Navy and are trained to detect underwater mines in the ocean.

While the videos revealed "absolutely fascinating" insight into how dolphins caught and consumed their prey, the scientists flagged one meal as a little unusual. One of the dolphins, born in captivity, was captured snacking on a highly venomous species of sea snake.

Researchers believed that was the first time dolphins had been recorded eating sea snakes, and they guessed the dolphin's lack of hunting experience may have had something to do with the unusual choice.

The footage forms part of an article published in the PLOS journal this week exploring the hunting and feeding habits of dolphins.

Australian researchers said the videos help answer some "lovely little questions" about dolphin behaviour, including how they could turn fish around in their mouths.

"Dolphins really have to swallow fish heads-first," Australian Dolphin Research Institute executive director Jeff Weir said.

"Unless it's a really slippery sucker, like an eel, they risk getting it stuck in their throat," he said.

Dolphins were almost always catching fish tail-first as the prey tried to get away, he said. So they had to re-orientate the fish while in their mouth.

"It's really given an insight to how they minimise escape using their throat."

The study was led by the late American scientist Sam Ridgway, a veteran dolphin researcher whose contribution to marine science was immeasurable, Mr Weir said.

The US scientist, who died this year, was a towering figure in the community.

"Sam is one of the granddads of dolphins," Mr Weir said.

"He was one of the real old-timers - he's actually a vet, and a lot of what we know about dolphins has come from Sam."

Read more

The six dolphins used in the study are owned by the US Navy and trained to detect underwater mines.

While Australia does not have military-trained dolphins, the US and possibly Russia have been training marine mammals for years, Mr Weir said.

"The US Navy have got facilities where they work with these animals, and they train them to recover people," he said.

While many people are opposed to training dolphins, Mr Weir said, studies like this would be impossible to do on animals outside of captivity.

"These things aren't black and white," he said.

"A lot of what we know today is from dolphins in captivity - the only way you could do this with a wild animal is to catch it in a net and risk drowning it," he said.

"That's a high risk to the animal, and it's very difficult."