Researchers have for the first time filmed rare True's beaked whales underwater. The deep-diving mammal is so rarely seen that researchers devoting their life to study whales have never seen a True's beaked whale.

The latest study, published in the journal Peerj, gathered stranding data and sightings in the Azores and Canary Islands.

These beaked whales break diving records, feeding at depths of up to 3 kilometres and lasting up to 2 hours.

Here's the first footage:

True's beaked whales have previously been spotted off the coast of Australia.

The whales, part of the Ziphiidae family including whales, dolphins and porpoises, are considered to be among the least understood mammals in the world.

The whales, growing to about 5 metres in length and weighing 1,400 kilograms (3,086 pounds), spend about 92 percent of their life underwater.

"Beaked whales are vulnerable to human impacts: mass strandings occur in relation to naval exercises using intense sonar signals to detect submarines," the researchers say.

"Also, whales appear on the beach with plastic inside their stomach, entangled in fishing gear or suffering cuts from boat propellers."

This article was originally published by Business Insider

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