Give or take a dozen years, the killer whale known as Granny may have been as old as 105 when she disappeared. A regular fixture among the southern resident killer whales of the Pacific Northwest, Granny — or J2, to the marine biologists who studied her — vanished last autumn.

Her disappearance was, in all likelihood, mortal. “Perhaps other dedicated whale-watchers have seen her since then, but by year’s end she is officially missing from the [southern resident killer whale] population, and with regret we now consider her deceased,” wrote Ken Balcomb, director of the Center for​ Whale Research in San Juan Island, Wash., on Saturday.

“I last saw her on October 12, 2016,” Balcomb wrote, “as she swam north in Haro Strait far ahead of the others.” That old female animals would lead a pod of whales was not unusual among the resident orcas; a 2015 study determined that postmenopausal killer whales took charge of their family groups during periods when salmon were scarce. (Humans, killer whales and short-finned pilot whales are the only three species known to live long after they cease reproducing. One hypothesis posits that a grandmother human or whale nurtures her descendants by sharing the knowledge she had gathered over a lifetime.)

It was impossible to know whether the centenarian cetacean was exactly 105, or a centenarian at all. But whale experts identified Granny first in 1976, distinguishing her from the other animals by a notch in her dorsal fin and the shape of the white patch on her back. Balcomb and the other biologists pegged J2’s age to that of the other whales in her group, presumably her offspring. “In 1987 we estimated that she was at least 45 years old and was more likely to have been 76 years old,” Balcomb wrote.

Even in her most senior years, J2 was capable of swimming hundreds of miles in just more than a week, to arrive at Puget Sound to hunt for fish. Granny lived through a series of remarkable events, some of which were disastrous for the resident whales. In the 1960s and 1970s, collectors scoured Puget Sound, catching orcas that would ultimately reside in Sea World or Marineland aquariums.

These whales, which were listed as endangered in 2005, once numbered as many as 140 animals; when the Chinook salmon numbers began to dwindle — coupled with exposure to pollutants that remain in the orca blubber — so too did the whales that fed on the fish. The loss of J2 brings the population to 78.

For Balcomb, Granny left behind a series of difficult questions in her wake. “Who will lead the pod into the future? Is there a future without food?” he wondered. And as for conservation of the whale habitat: “What will the human leaders do?

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