After a grueling research effort off the coast of Mexico, a rare yellow-billed whale has been seen and photographed alive at sea for the first time, a new study has found.
The newly sighted cetacean is a beaked whale (Mesoplodon ginkgodens), a member of the Gingkoidae family, previously only known from beach carcasses and bycatch. For beaked whales, this is not all that unusual. Beaked whales are known for their deep diving, cryptic nature, and spend their entire lives away from shorelines.
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The search and subsequent discovery of this elusive creature was prompted by the recording of distinct echolocation pulses in the North Pacific Ocean. Researchers began searching for the animal responsible for the mysterious sonar signals in 2020, and discovered a beaked whale in June 2024. Within days of the sighting, the team spotted a small group of whales, including a battle-scarred adult male and an adult female with a calf.
Beaked whale species are difficult to tell apart, so just observing the whales wasn’t enough to identify them. The researchers only confirmed the discovery after shooting one of the whales with a crossbow and taking a DNA sample. (Don’t worry, the whales are fine.)
The researchers will publish their findings online on July 28 in the journal Marine Mammal Science, and will appear in the journal’s upcoming January 2026 issue. Lead study author Elizabeth Henderson, a bioacoustic researcher at Naval Information Warfare Center Pacific, said the findings show the benefits of determination and not giving up.
“Myself and several others on this trip (Gustavo Cárdenas, Jay Barlow) spent five years searching for these whales. We’ve spent every year since 2020 locating them off the coast of Baja. That hard work and determination has paid off with huge rewards,” Henderson told Live Science in an email.
The seijō toothed whale got its name because the male’s pair of teeth resemble the fan-shaped leaves of a ginkgo tree. In whales, almost all of this shape is hidden in the jaw and gum tissue, with only the tips of each tooth visible on each side of the mouth. The teeth grow into small fangs as the male grows, and are used as weapons rather than for eating.
“They feed on small squid and fish by suction feeding, so they don’t need teeth,” Pittman said. “As a result, females remain toothless throughout their lives, while males leave a pair of enlarged teeth in their lower jaws that they use as fangs to fight for access to fertile females.”
When the researchers finally tracked down the whales, they found an adult male with worn tusks, bruises and scars, and a seemingly battle-hardened appearance. Other whales recorded by the researchers in six separate observations were also marked, but they weren’t the only ones. Their scars included distinctive white lumps indicating they had been bitten by cookie cutter sharks (small sock puppet-like fish that tear cookie-shaped chunks out of larger animals and eat them).
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The research team recorded the whales using binocular observations, photographs, and hydrophones. During the fifth encounter, one of the whales swam within 66 feet (20 meters) of the stern of the researchers’ boat, when Pittman fired a 150-pound (68-kilogram) draw-weight crossbow loaded with a modified punch-tipped arrow.
“The crossbow arrow (‘bolt’) extracts a small plug of skin and fat about the size of a pencil eraser,” Pittman said. “Over the years, we have collected thousands of whales and dolphins from dozens of species.”
Henderson compared firing a crossbow to an earshot, but Pittman pointed out that a bite from a cockcutter shark would probably require 50 times more tissue than a crossbow. The arrow did not pierce the whale, so researchers were able to recover the arrow and tissue. With the sample in the bag, the researchers sent the tissue to a geneticist for testing.
“It took several days to process the materials and run the tests, and we all waited with bated breath,” Henderson said. “When the results came back, we were all a little shocked. It certainly looked like the species, but this wasn’t the expected distribution area, so we dismissed it as a possibility. But at the same time, we were all excited that the mystery was finally solved.”
Ginkgo’s beaked whale strandings are fairly common in the Western Pacific, but two strandings have been recorded in the Eastern Pacific. Researchers initially suspected the whale they were observing was a beaked whale (Mesoplodon perrini), but Pittman said the whale is known only from six specimens that washed ashore off the coast of Southern California, making it the world’s least-known marine mammal (and large animal).
Pittman said the team now hopes to go in search of the Perrin’s beaked whale and two other species of beaked whales that are not known to be alive in the wild, and face further calls underwater.
“This is important because collating the calls of all individual species allows us to use passive acoustic monitoring (towing a hydrophone behind a ship, a drifting buoy, etc.) and ultimately tell us where these whales live, how many there are, and how vulnerable they are to human disturbance, especially fishing on the high seas,” Pittman said.
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