Scientists say they’ve found a previously unknown whale species – a ‘one tonne’ mammal the size of a horse and may have been on the planet as long as humans.
Three specimens of the as-yet-unnamed species, a type of beaked whale, were seen in waters near the San Benito Islands off the coast of Mexico.
US scientists took photos and video of the animals and deployed a specialised underwater microphone to record the acoustic signals emitted by the whales, known as echolocation signals.
Whales use echolocation – sensing objects from reflected sound waves that they emit – for hunting and navigation.
After studying the underwater photographs, experts noticed the tusk of the animals are in a completely different place from any other beaked whale, while its distinctive echolocation signals are also previously unknown.
Experts are ‘highly confident’ that the photographic and acoustic evidence reveals the presence of an entirely new whale species.
Photographs of the new species of beaked whale. The fact it is previously unknown to science was indicated by the position of its tusks and its echolocation signals
The three whales were seen in waters 100 miles north of the San Benito Islands, a group of three remote islands located approximately 300 miles from the US border.
‘We saw something new, something that was not expected in this area, something that doesn’t match, either visually or acoustically, anything that is known to exist,’ said Dr Jay Barlow at the Scripps Institution of Oceanography in San Diego, who led the expedition.
‘It just sends chills up and down my spine when I think that we might have accomplished what most people would say was truly impossible – finding a large mammal that exists on this earth that is totally unknown to science.’
Dr Barlow described discovering the new species as ‘probably what was the biggest surprise of my life’.
Two of the newly found specimens. They were identified as beaked whales from their moderate size and distinctive ‘beak’ like a dolphin’s
The sightings occurred 100 miles north of Mexico’s San Benito Islands, a group of three remote islands located approximately 300 miles from the US border
Environmental genetic sampling, performed at the time of the sighting, is undergoing analysis and is expected to prove the existence of this new species definitively
‘People discover new species of beetle practically every year but we’re talking about a mammal here that’s the weight of a large horse,’ Dr Barlow told BBC Radio 4’s Today programme on Wednesday morning.
‘It’s a one-tonne animal that’s co-existed on this globe with us for as long as we’ve been here and yet no-one has classified it, no-one has recognised it as being something different.’
Beaked whales, like all cetaceans, emit distinct acoustic echolocation signals under the water.
These sounds are unique to each species and can reliably identify the types of beaked whales present in the area.
The Martin Sheen, owned and operated by the Sea Shepherd Conservation Society, sits off in another location scanning for the beaked whales
‘The beaked whales all make these very characteristic echolocation pulses and they use it to find their food source,’ Dr Barlow told Radio 4.
‘They make a pulse, they wait for it to return and they can tell the range and distance to the food that they’re looking for.
‘Beaked whale echolocation pulses are quite distinct because they have this characteristic upsweep to them.’
The discovery was by chance, as scientists had been investigating another species already known to science.
Back in 2018, the team recorded an unknown acoustic signal in the waters north of the San Benito Islands.
The signal, known as BW43, had been detected off the coast of California, and scientists believed it could be the sound of a species called Perrin’s beaked whale (Mesoplodon perrini), which is known to science but has never before been seen live in the wild.
The crew work right until sundown looking for Perrins beaked whales – a totally different species from the one they ended up finding
The population size and geographic range of Perrin’s beaked whale, which is one of 23 known species of beaked whales found in oceans around the world, are unknown.
So on the morning of November 17 this year, the expedition on board Sea Shepherd vessel Martin Sheen set off to possibly link BW43 with Perrin’s beaked whale.
The team used underwater microphones called ‘hydrophones’ to record echolocation.
What they observed instead was the three unknown beaked whales surfacing in the waters off of Mexico’s San Benito Islands.
They were identified as beaked whales from their moderate size, their distinctive ‘beak’ like a dolphin’s and the fact they surfaced very close to the boat.
But the three specimens were not Perrin’s beaked whales or any other known species.
And the acoustic signal emitted by the unknown species was not BW43 or any other sound known to science.
‘What we ended up discovering when we saw the sighting was something completely different – I didn’t realise they weren’t Perrin’s beaked whales until we started looking at the photographs,’ Dr Barlow told Radio 4.
‘A colleague in the vessel with me showed me a photograph – it had a tooth exposed in the adult male (as they do, it’s more a tusk) but it was in the wrong place for where we were looking for,’ Dr Barlow told Radio 4.
‘At that point I realised we had something very different, something unexpected from the area.
‘But it wasn’t until I looked at the acoustic signals that we recorded in the same area a few hours later that I realised really how different it was, because the echolocation signals didn’t match any known species.’