For the very first time, scientists have spotted a living ginkgo-toothed beaked whale, a rare, deep-diving species that until this sighting had previously only been known from a handful of strandings.
These elusive whales were only described for the first time in 1958, after one became stranded on a beach near Tokyo. That ended up setting the tone for the next 66 years, with only a sparse number of sightings since then and all of them also involving dead whales. Researchers may have spotted a living ginkgo-toothed beaked whale in 2021 in the South China Sea, but it wasn’t confirmed.
At the same time, there was a mystery afoot in the North Pacific. Beaked whales are known to produce calls (the more formal term is echolocation pulses) unique to each species, and in this region of water, acoustic monitoring had picked up one known as BW43 – but it wasn’t clear which species it belonged to.
Some researchers thought it could be the call of Perrin’s beaked whale, another species that had never been seen alive. Following concentrated detections of BW43 in 2018 in Baja California, the first expedition in search of these whales set off in 2020.
There were no sightings – and there weren’t for the next three years’ worth of surveys either. Scientists, however, are nothing if not persistent in the face of a mystery. In June 2024, with hydrophones and high-powered binoculars in tow, they set out on a fifth expedition to find the source of BW43.
They struck gold, making six beaked whale sightings – none of which would turn out to be Perrin’s beaked whale. Visuals and acoustic detections weren’t enough to conclude that any were ginkgo-toothed beaked whales though; they can easily be mistaken for other beaked whale species.
That’s where genetic analysis comes in, and that requires taking a sample of DNA. Seeing as you can’t really ask a whale to spit into a tube, this ended up involving a modified crossbow to collect a skin biopsy from one of the sighted whales.
The researchers did so successfully – until an albatross appeared and decided a hunk of whale skin would make a great snack. Luckily, the team was able to scare the bird away. “In hindsight, it is very funny, but in the moment it was very stressful,” lead study author Elizabeth Henderson told The Guardian.
Genetic analysis of the sample confirmed that this was indeed a gingko-toothed beaked whale. In fact, five of the six sightings were determined to involve the whales, with a mature adult male – covered in scars suspected to have been made by cookiecutter sharks – a young adult male, adult female and calf, and juveniles all spotted.
An adult female gingko-toothed beaked whale swimming with a calf.
Not only did this mean finally identifying the source of BW43, but also the first-ever sighting of a living gingko-toothed beaked whale.
Like other beaked whales, little is known about the species, but the sightings have provided fresh details. For example, the team was able to describe the color pattern of juvenile members of the species – something that had never been done before. “All had a slightly paler head and melon compared to the back, dark eye patches, and a pale eye spot in front of and slightly above the eye patch,” write the authors in the study describing the sightings.
The observations also appear to suggest that gingko-toothed beaked whales are “a fairly widespread, if uncommon, resident off California and Baja California,” the authors write, stating that these whales “occur far more regularly in the eastern Pacific than previously assumed.”
Now knowing the call of these elusive whales, it’s hoped that this is just the beginning of uncovering the species’ mysteries. “With this identification, we can begin to fill in more information on the behavior and distribution of the ginkgo-toothed beaked whale,” the authors conclude.
The study is published in Marine Mammal Science.
[H/T: The Guardian]
Source Link: Elusive Gingko-Toothed Beaked Whale Seen Alive For First Time Ever
