Rare tusked whales have been identified and photographed alive at sea for the first time following a herculean research effort off the shores of Mexico, a new study finds.
The newly-sighted cetaceans are ginkgo-toothed beaked whales (Mesoplodon ginkgodens), which were previously only known from dead individuals that had washed ashore and from bycatch. This isn’t all that unusual for beaked whales, which are deep divers and notoriously cryptic, spending their lives away from coastlines.
The hunt for and subsequent discovery of the elusive creatures was sparked by a recording of a distinct echolocation pulse in the North Pacific. Researchers began searching for the animals responsible for the mysterious sonar signal in 2020, and in June of 2024, it led them to a single beaked whale. Within days of that sighting, the team then found a small group of the whales, including a battle-scarred adult male and adult female with a calf.
Beaked whale species can be difficult to tell apart, so simply observing the whales wasn’t enough to identify them. The team only confirmed what they had seen after collecting a DNA sample by shooting one of the whales with a crossbow. (Don’t worry, the whale is fine.)
The researchers published their findings online July 28 in the journal Marine Mammal Science, which will appear in the upcoming January 2026 issue of the journal. Study lead author Elizabeth Henderson, a bioacoustic researcher at the Naval Information Warfare Center, Pacific, said that the findings demonstrated the benefits of determination and not giving up.
“Myself and some of the other folks on this trip (Gustavo Cardenas, Jay Barlow) spent five years looking for these whales; we spent every year since 2020 searching off Baja to find them, and that effort and determination paid off with a huge reward,” Henderson told Live Science in an email.
Ginkgo-toothed beaked whales are so named because the males have a pair of teeth that resemble the fan-shaped leaves of a ginkgo tree. For the whales, almost all of this shape is hidden in the jaw and gum tissue, with only the tip of each tooth visible on either side of their mouth. The teeth grow into small tusks as the males mature, and aren’t for eating, but are used as weapons.
“They feed on small squids and fishes by suction feeding, so they don’t need teeth,” Pitman said. “As a result, females are toothless their entire lives, but males retain a single pair of enlarged teeth in the lower jaw that they use as tusks to fight over access to reproductive females.”
When the team finally tracked down the whales, they saw that one adult male was seemingly battle-hardened with a worn tusk, bruising and scars. The other whales the researchers recorded across six separate observations were marked, too, and not just from other whales. Their scars included distinctive white blobs indicative of bites from cookiecutter sharks — little sock puppet-like fish that feed by ripping cookie-shaped chunks out of larger animals.
The team documented the whales with binocular observations, photographs and hydrophones (underwater microphones). During the fifth encounter, one of the whales swam within 66 feet (20 meters) of the stern of the researchers’ ship, which is when Pitman fired his 150-pound (68-kilogram) draw-weight crossbow loaded with a modified punch-tip arrow.
“The crossbow arrow (‘bolt’) extracts a tiny, pencil-eraser-sized plug of skin and blubber,” Pitman said. “We have collected thousands over the years, from dozens of whale and dolphin species.”
Henderson compared the crossbow shot to an ear-piercing gun, while Pitman noted that any one of the whales’ cookicutter shark bites probably took 50 times more tissue than the crossbow. The arrow didn’t stick in the whale, so the researchers could retrieve it and the tissue. With a sample in the bag, the researchers then sent the tissue to a geneticist for testing.
“It took a few days to process the material and run the tests, and we were all waiting with baited breath,” Henderson said. “When we got the results back we were all a bit shocked — while they did look like that species, this was not the expected area of their distribution so we had discounted that as a possibility — but we were also thrilled to finally have the mystery solved.”
Ginkgo-toothed beaked whale strandings are fairly common in the western Pacific, but only two individuals have ever been recorded stranding in the eastern Pacific. The researchers had initially suspected that the whales they were seeing were Perrin’s beaked whales (Mesoplodon perrini), which Pitman said are known from only six stranded specimens off southern California and are the least known marine mammals (and large animals) in the world.
Pitman noted that the team now hopes to go looking for Perrin’s beaked whales and the two other species of beaked whales that have yet to be identified alive in the wild, putting faces to more underwater calls.
“This is important because once we match up the calls to all the individual species, then we can use passive acoustic monitoring (towing hydrophones behind vessels, drifter buoys, etc.) and finally learn where these whales live, how many there are, and how vulnerable they are to human disturbances, especially high-seas fisheries,” Pitman said.
Published Date : 2025-11-21 18:55:00
Source : www.livescience.com
