An orca named J35 has finally dropped her dead calf, which she'd been pushing with her head for at least 17 days and 1,000 miles off the Pacific Northwest coast, in an unprecedented show of mourning that drew international attention.

The sad spectacle was a prime example, and confirmation, of the complex emotional lives of these sophisticated cetaceans, experts say.

Other orcas, and similar animals like dolphins, have been seen apparently mourning their dead, but this is by far the longest recorded example of such behavior.

J35, nicknamed Tahlequah, is a 20-year-old member of the long-studied J Pod of Southern Resident Killer Whales. These orcas, along with their endangered extended family—K and L pods—inhabit a huge territory that includes waters off Seattle, Vancouver, and Victoria, British Columbia.

Researchers worried that this "tour of grief" might seriously endanger the health of J35, but luckily, she appears to have made it through physically unharmed. "Telephoto digital images taken from shore show that this mother whale appears to be in good physical condition," the Center for Whale Research noted in an update, "following her record-setting ordeal.

As J35’s sojourn continued, some experts wondered why she was so attached to the calf. Was it because the calf lived for about 30 minutes after it was born? Jenny Atkinson, executive director of The Whale Museum in Friday Harbor, British Columbi, thinks the grief Tahlequah is feeling is deeper because after 17 months of gestation, she then had the chance to form an emotional connection with her baby before it died.

“I think that’s quite possible,” says John Ford, an orca researcher at the University of British Columbia. “The whales have a very strong drive to look after their offspring and this evidently extends to neonates that die at birth.”

The death of another calf is a significant blow to J Pod, which hasn’t seen a successful birth in three years. Combined, the three pods have 75 members, and time is running out to maintain its viability. Ken Balcomb, founder and principal investigator at the Center for Whale Research, gives it five years.

“We’ve got at most five more years of reproductive life in this population to make it happen”—meaning, to have viable offspring—"but if we don’t do it in those five years it isn’t going to happen,” he writes.

View Images J35 carried her calf for at least 17 days and 1,000 miles, and researchers had worried she'd endangered herself by expending so much effort. But now she appears in good health. Photograph courtesy Center for Whale Research (Permit #21238)

Balcomb points to a lack of food as the culprit. “We have long demonstrated that these fish-eating whales are getting skinnier and skinnier, and the death rate is increasing,” he writes on the center’s website.

“Whales in this endangered population are dependent upon Chinook salmon for their primary food source. Unfortunately, Chinook salmon are also endangered,” he adds.

Experts expressed relief that J35 survived. As a 20-year-old in her prime, the pod needs her to reproduce.

“Even without this death, this is a population in crisis,” Atkinson says. “They need our stewardship and support if they are to survive.”