This is the heartwarming moment a giant, 50,000-pound humpback whale protects a marine biologist from a nearby shark by shielding her and pushing her out of harm's way.

The hypnotising footage was filmed in the waters off Muri Beach, Rarotonga, of the Cook Islands in the South Pacific.

Whale biologist Nan Hauser says the humpback protected her and her team from a circling tiger shark by putting her under its fin and using his head and mouth to push her away.

This is the heartwarming moment when a giant, 50,000-pound humpback whale protected an unaware snorkeler from a nearby Shark as it pushed her out of harm's way

The 50,000lb mammal can also be seen tucking the 63-year-old under its pectoral fin and it even lifts the biologist out of the water at one point.

Nan said the incident, which occured in October, is proof of the whale's intuitive nature to protect other species of animal - including humans - something she believes has never been captured on film.

The biologist compared this to firemen being willing to rush into a burning home to help save the lives of strangers.

Surrounding the unsuspecting snorkeler and the roughly 14-metres-long mammal was a 15-foot tiger shark.

The hypnotising footage was filmed in the waters off Muri Beach, Rarotonga, of the Cook Islands

Marine biologist Nan Hauser said the incident, which occured in October, is proof of the whale's intuitive nature to protect other species of animal - including humans - something she believes has never been captured on film

FIERCE PROTECTORS: Why do humpback whales shield other species from attack? Mothers protect their calves by smacking their massive tails or swinging their 5-meter-long, barnacle-encrusted fins. But this behaviour is not reserved only for kin as scientists have found humpbacks to shield other species from attack. Experts so far can't pin-point why the mammals would risk their survival for a different species but the most widely accepted view is that the altruistic behaviour is a 'spillover'. Altruistic behaviour is where your actions are an advantage to someone else but end up costing you. Scientists explain that the humpback whale might exhibit this characteristic as it is an extension of their drive to protect their own calves. Not many predators can harm the mammals so instead of being on the defence they have learnt to attack the threats head on and drive them away. Researchers believe that rather than protecting a specific species, it may be an act of dominance over the predators - to try and ensure they don't return when calves are around. Advertisement

The footage shows the whale guiding the diver into a certain direction and it's not longer before Nan breaks the surface and reveals to her team on board a boat that there is a shark nearby.

Nan says that out of shot, another whale was using his tail and slapping the water to divert the shark away, she told the Mirror.

Initially the snorkeler presumed the shark was another whale coming to join the fun - it was only when she saw its tail moving left to right instead of up to down that she realised it was in fact a more menacing animal swimming towards her.

The footage captures the moment Nan returns to safety and the whale can even be seen peeking above the water to check up on his new friend.

Nan, who lives on the Cook Islands, said: 'I wasn't sure what the whale was up to when he approached me, and it didn't stop pushing me around for over 10 minutes.

'I've spent 28 years underwater with whales, and have never had a whale so tactile and so insistent on trying to tuck me under his huge pectoral fin.

'In my head, I was a bit amused since I write Rules and Regulations about whale harassment - and here I was being harassed by a whale'

Scientists have seen cases of whales protecting other species but this will be the first documented case where they've actually protected humans from a shark, Nan said.

She added: 'It's funny how the tables are turned here: I've spent the past 28 years protecting whales, and in the moment, I didn't even realise that they were protecting me!'

'I've spent 28 years underwater with whales, and have never had a whale so tactile and so insistent on trying to tuck me under his huge pectoral fin'

Scientists have seen cases of whales protecting other species but this will be the first documented case where they've actually protected humans from a shark, Nan said