The orca known as J35 (Tahlequah) carries the carcass of her dead calf in the waters of Puget Sound off West Seattle, Wash., on Jan. 1.Candice Emmons/The Associated Press
A killer whale that is part of a population struggling to survive appears to be grieving, carrying the carcass of her dead calf on her head, echoing the mourning behaviour she exhibited for 17 days when another one of her offspring died in 2018.
The mother orca, known as J35 or Tahlequah, is a Southern Resident killer whale in the Salish Sea off the coast of British Columbia and northwest Washington State. In July, scientists counted 73 Southern Residents, with 25 in the J pod. The deceased calf was a female, designated J61, and only lived for a few days in December.
Southern Residents are endangered, and Canada and the United States have imposed marine buffer zones and other measures to protect the whales. During a press briefing this week detailing J pod’s latest adventure in reproduction, scientists in the U.S. said they do not expect to be able to pinpoint J61’s cause of death, but believe a dearth of Chinook salmon will make it difficult for Southern Residents to survive.
Researchers observed the J pod in Puget Sound, which is part of the Salish Sea, on Dec. 19, and did not spot any calves. The next day, members of the public reported sightings of a newborn in the waters near Seattle. Scientists located J35 and J61 on Dec. 23, and mother and baby were both struggling. That was the last time J61 was documented alive. Now, J35, who has raised two sons, is refusing to let her deceased calf fall into the depths of the Pacific.
Joe Gaydos, the science director for the SeaDoc Society, said it is fair to anthropomorphize J35’s response as grief or mourning.
“We have the same neurotransmitters that they have. We have the same hormones that they have. Why shouldn’t we also have the same emotions?” he said during the news conference Thursday. “We don’t have the market cornered on emotions.”
Other long-living and socially-cohesive animals, such as dolphins and primates, exhibit similar behaviour, he added. “From a scientific perspective, if they have the same hardwiring, they are going to have the same emotions.”
Southern Residents produced three calves in 2024: one in L pod, which subsequently died; the deceased J61; and J62, which appears to be healthy, scientists said on the media call. Researchers have determined neither J62’s sex nor its mother.
The whale population is threatened by everything from pollution to inbreeding, and the Southern Residents are at heightened risk. Michael Weiss, the research director at the Center for Whale Research, said when scientists run scenarios projecting the Southern Resident population, few models result in the population bouncing back. For these orcas, the winning calculations share a universal factor: more Chinook salmon.
“You can’t get recovery of the population without boosting the food available to them,” he said.
The Southern Resident birth and survival rates, scientists said, are anomalously low compared to other killer whales. The nearby Northern Resident population is more successful at reproducing and the West Coast Bigg’s killer whales, which share the same habitat, even more so. Females in this population get pregnant almost immediately after producing offspring and are able to keep their calves alive.
Scientists said the Bigg’s population owes its advantage to diet; these whales eat marine mammals like seals, sea lions and porpoises, which the whales can find in abundance.
Brad Hanson, a research scientist with the National Oceanic and Atmospheric Administration in the U.S., said fewer fish are available to Southern Residents this time of year. Scientists have not observed the mourning mother orca foraging for food and speculate, without visual confirmation, that other pod members may be sharing their catch with her.
J35’s sister has been sticking close by, scientists said. Some whales appear to be engaging with J35 and her calf, scientists said, conceding it is unclear whether the other whales are showing interest or concern for the deceased pod member, her mother, or just travelling in the same direction.
Mr. Hanson said these whales typically have a five-year gap between offspring, because calves wean after three years and the gestation period is 17 months. The researcher noted J35 birthed a son four years ago, which may have contributed to the baby’s death.
“She may not have had time to physically recover from her prior calf,” he said. Further, calves born to mothers with more sons are less likely to survive; J35 already has two male offspring, the scientists noted. The calf that died in 2018 was female.
Scientists said they do not know why J61 died and it is unlikely they will be able to perform a necropsy. They estimated around 70 to 80 per cent of known killer whale calves survive, but the actual rate could be around half when accounting for offspring that die without ever being documented by scientists.