A gift of dried whale meat—and some clever genetic sleuthing across almost 16,000 kilometers of equatorial waters—has helped scientists identify a long-forgotten animal as a new species of beaked whale. The “resurrection” raises new questions about beaked whales, the most elusive and mysterious of cetaceans.
“Literally nothing is known about most species of beaked whales; they are probably the least known family of large mammals,” says Robin Baird, a cetacean biologist at Cascadia Research Collective in Olympia. “So it’s exciting to have this study.”
The species, Mesoplodon hotaula, is a dark blue, Volkswagen-van-sized cetacean with the prominent snout that gives beaked whales their common name. It first came to scientists’ attention in 1963 when a single adult female stranded on the coast of Sri Lanka in the Indian Ocean. The director of the National Museums of Ceylon, P. E. P. Deraniyagala, decided that it was different from the other Mesoplodon species known at that time, and assigned it the name hotaula, meaning “pointed beak” in the local Sinhala language. But only 2 years later, M. hotaula was eliminated as a species when other researchers decided that it was identical to M. ginkgodens (another beaked whale which scientists know only from stranded carcasses and have never seen alive in the sea).
Forty years later, locals on an atoll in the Gilbert Islands, part of the Republic of Kiribati in the west Pacific, gave a visiting marine biologist dried strips of whale meat left over from a recent festival. The sample was turned over to cetacean geneticists at the University of Auckland in New Zealand who had assembled a database of the DNA of all known beaked whales. “It was a surprise, because the genetic sequences from the meat didn’t match any of the known species,” says Scott Baker, a cetacean geneticist now at Oregon State University’s Marine Mammal Institute in Newport, and one of the authors of the study. “We thought we had a new species.”
Then, in 2005, other co-authors collected some whale bone and teeth on Palmyra Atoll, which lies southeast of the Hawaiian Islands and 2600 kilometers northeast of the Gilbert Islands. The genetic sequences extracted from these specimens matched those of the dried meat. “We knew then we were on to something,” Baker says. Finally, in 2009, the body of a beaked whale was found in the Seychelles, in the western part of the Indian Ocean; its DNA also matched that of the dried meat sample, even though this whale lived tens of thousands of kilometers away from the Gilbert Islands.
That was the clue the researchers needed. “We immediately wondered, ‘Could it be Deraniyagala’s beaked whale?’ ” Baker says. It was. The team recently reported its resurrection of the forgotten M. hotaula in Marine Mammal Science. Counting M. hotaula, there are now 15 known species in this genus, making it by far the most species-rich genus of cetaceans.
Overall, the saga of M. hotaula shows “that there are probably even more species of beaked whales that we don’t know about,” says Phil Clapham, a marine mammalogist at the National Marine Mammal Laboratory in Seattle, Washington. “We don’t see them because they’re very deep-diving and live far from land.” They also live in a poorly surveyed part of the ocean, Baker says, where very few people dwell on remote atolls.
Intriguingly, it is the islanders who seem to know the most about M. hotaula and some other beaked whales. The Gilbert Islands residents who provided the original gift of dried meat reported that it came from one of seven whales they had driven onto the beach and killed. “That was something we didn’t know: that these beaked whales live in groups,” Baker says. “We thought they were solitary” because of the single, stranded individuals that are occasionally found. The scientists also believe that males of M. hotaula fight each other, because this behavior is known in other species of beaked whales, and because the teeth of two adult male specimens were broken. “Other than that, and knowing that Deraniyagala was right, M. hotaula is still pretty mysterious,” says Baker, who hopes to launch an expedition to learn more about them.
Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.