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The sighting of a rare True’s beaked whale came literally out of the blue, and it’s been captured on video.

The first underwater footage of this elusive mammal was recorded in the deep coastal waters of the Azores and shows three of the whales surfacing.

Just seven live sightings have been reported in Macaronesia, the southernmost part of their north Atlantic range, and some may be misidentifications of other beaked whale species.

The new video was taken by a team of educators on an expedition with a group of schoolchildren. The whales surfaced for 10 minutes, which gave the team time to slip out of their inflatable boat with a GoPro camera to record them.

“Suddenly this group of whales appear from nowhere and start to surround the boat,” says , a marine biologist from the University of St Andrews, UK, and the University of La Laguna on the Canary Islands, Spain, who later identified the whales from the footage. “These are whales that very few people in the world have ever seen.”

The True’s beaked whale has never been tagged for research purposes, but other beaked whale species have and they all exhibit the same behaviour.

Deepest divers

They dive for an hour, sometimes two, and surface for just a few minutes to take a series of rapid breaths before diving again. And they go deep, routinely reaching one kilometre beneath the surface. Some have been measured as far as 3 kilometres down.

To glide through the water more efficiently, beaked whales have indents in their sides like little pockets where they put their flippers. “If you want to be 2 hours under the water with only the oxygen you keep in your body, any energy [saving] counts,” says Aguilar de Soto.

The video clearly shows a white patch on the whales’ heads, an identifying feature of the True’s beaked whale.

The pale spot covers the melon, an area of tissue between the blowhole and snout that focuses the clicks they use for echolocation. The markings extend further along the head than had previously been seen for the species.

White beanie

“The white on the melon, it’s sometimes called a white beanie because it looks like a beanie cap,” says , a marine mammal biologist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center in California. “What they pointed out is that there seems to be variation in that colour pattern and sometimes the white extends much further to the anterior, into the beak, and around the eye.”

“Apparently we didn’t know as much as we thought we knew about the colour and pattern,” Barlow says.

This kind of footage helps scientists learn to identify True’s beaked whales on future sightings. Most of what we know about this species comes from whales stranded on beaches, whose skin can darken from exposure to the sun.

Knowing what these whales look like will also help researchers monitor population sizes, Barlow says. Right now, there’s too little data to even estimate the number of True’s beaked whales in the ocean.

“We know that some species of beaked whale are very vulnerable to navy sonar. We want to monitor those species and determine if they’re being impacted. The only way to be able to do that is to tell them apart at sea,” Barlow says.

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