We humans are compassionate animals, partly because we're good at spotting cause-and-effect relationships. For instance, we've all personally experienced some form of loss and the pain that comes with it, so when we see someone else grappling with the loss of a loved one, we understand, we relate, we feel their pain.
It's sometimes hard to find causal relationships in the behavior of nonhuman animals, but there's something about grief: We know it — and we feel it — when we see it. Which is why Southern Resident Orca J35, or Tahlequah, the 20-year-old killer whale whose calf died only a half hour after birth on July 24, 2018, near Victoria, British Columbia, got so much attention. People from all over the world were riveted as the mother killer whale lugged the body of her dead calf around the Salish Sea. On Aug. 9, The Seattle Times reported that Tahlequah was still clinging to her baby, keeping its 400-pound (180-kilogram) body afloat with her head, coming up for air and swimming in a tight circle behind her pod for a few breaths before diving down deep to lift her daughter's body to the surface again.
It was hard to watch, but for all those days, Tahlequah was traveling 60-70 miles (97-112 kilometers) a day in strong current with her baby's corpse on her head, showing us what grief looks like. Scientists had no plans to take the calf away from J35 or her pod, noting the "tight bond," reported The Seattle Times.
Killer whales, though they have a reputation for being ruthless predators, are some of the most socially sophisticated animals in the world. Their brains are complex — bigger and more complicated in some respects even than our own. We know they're capable of emotions like grief because the parts of their brains that do social and emotional work are big and elaborate, and they even contain specialized empathy cells called von Economo neurons, which help highly social animals like primates, elephants and whales achieve the extreme levels of cooperation that's required of them.
Unsurprisingly, given their neuroanatomy, orcas live in tight-knit matrilineal pods that are led by mothers, aunties and grandmothers — female orcas have the longest post-menopausal life span of any animal we know of besides humans. Females reach sexual maturity in their teens, and their fertility starts to wane in their 30s or 40s, yet they have been known to live more than a century, spending their postreproductive years helping their daughters and granddaughters raise babies. Tahlequah was not carrying that calf's body all by herself — members of her family helped her with her vigil.
But even with female role models in abundance, orcas share an unusual bond with their mothers. According to a 2012 study, a male killer whale over the age of 30 is three times more likely to die within a year after his mother's death. And although Tahlequah's period of mourning was longer than most researchers have believed possible (The Center for Whale Research observed that Tahlequah had ended her grieving process on Aug. 11), she was certainly not the first mother orca to engage in what researchers are calling a "tour of grief" with her deceased calf. A 2016 study described 14 cases of "nurturant behavior" toward dead calves in seven species of marine mammals, including orcas. The study suggests that after a 17-month pregnancy and the promise of a two-year period of nursing and constant mother-baby togetherness, the mother orca might just have needed time to adjust to the idea that her calf was dead.
And unfortunately, we all need some time to adjust to the death of baby orcas, because it's been happening a lot more often. Tahlequah is a member of the Southern Resident killer whale population, a group that hangs out between the northern coast of British Columbia and the Puget Sound to the south. It's made up of three pods, all of which have been listed as endangered in both the U.S. and Canada. The population has decreased from 98 whales in 1995 to just 75 today, and many of its females are growing too old to reproduce. It has been three years since the population has had a new baby — under normal circumstances four or five calves would be born each year to this group.
Researchers blame starvation for the recent plummet in Southern Resident killer whale numbers. Chinook salmon, their primary source of food, has been in a steep decline since the 1980s due to overfishing, habitat destruction and contaminated waters. Other dangers like boat traffic and noise threaten the killer whales as well.
In the meantime, babies need to be born while there are still fertile females in the population.
"Once they stop reproducing, they may still swim around here for 50 more years, but there will be no babies," Ken Balcomb, founder and chief scientist for the San Juan Island-based Center for Whale Research, told The New York Times. "Functionally, they will be extinct."
Editor's note: This story has been updated to reflect that Southern Resident Orca J35 ended her "tour of grief" by Aug. 11.