Of all the whales, in all the oceans, in all the world, the Omura's whale might be the most mysterious. So mysterious that we don't even know how many of them are cruising around out there – and until recently, not a single confirmed sighting of these elusive creatures had been recorded. Which is why this footage is pretty darn special:

The clip, filmed off the coast of Madagascar, comes courtesy of an international team of biologists who've made the first-ever field observations of Omura's whales, with as many as 44 groups spotted over a two-year period.

Their findings were recently published in the Royal Society Open Science journal, shedding light on things like where the whales like to hang out, how they go about foraging for food and even details about their song-like vocalisations. 

"Over the years, there have been a small handful of possible sightings of Omura's whales, but nothing that was confirmed," explains lead researcher Salvatore Cerchio in a press release. "This is the first definitive evidence and detailed descriptions of Omura's whales in the wild and part of what makes this work particularly exciting."

For years, Omura's whales (Balaenoptera omurai) were misidentified as Bryde's whales thanks to their similar appearance, until scientists managed to confirm they're a distinct species back in 2003 by analysing the few samples in existence. "What little we knew about these whales previously came primarily from eight specimens of Omura's whales taken in Japanese scientific whaling off the Solomon and Keeling Islands and a couple strandings of dead animals in Japan," says Cerchio.

Omura Whale _2015_10_30
The lives of Omura's whales are a mystery to us. In fact, scientists don't even know how many of them exist. Image: Cerchio et al. 2015.

Though their smaller size (around 33 to 38 feet in length) and unique markings distinguish the species from the Bryde's whale, it's still easy to confuse the two – in fact, that's exactly what happened when Cerchio and his team spotted their first Omura's whale off the northwest coast of Madagascar. More sightings followed, and the unique pigmentation on the whales' heads eventually convinced the team they were dealing with something very special.

During the course of the research, they managed to collect skin samples from 18 adult whales (which were analysed to confirm the species) and even to record the whales' song-like calls. They also used photographs to identify and catalogue about 25 individuals.

So what's next?

Cerchio, who's now based at the New England Aquarium (NEAQ), is planning to head back out into the field next month to learn more about his elusive subjects. He's hoping to gather more information about their vocalisations and behaviour – and then perhaps have a go at estimating just how many Omura's whales might be out there.

Video & top header image: Salvatore Cerchio