A mystery unfolds of an orca that washed up on Carmel River State Beach last fall.

On a warm Tuesday last fall, crowds gathered at Carmel River State Beach to witness something unusual: a live, beached, juvenile killer whale. “It literally looked like a movie scene,” said Wendy England, who was visiting on vacation from Colorado. “Everybody just wanted to come and help.”

The orca was reported “thrashing in the waves” to the Marine Mammal Center hotline at 7:25am on Sept. 10. Experts from the Center were dispatched immediately, joined by State Parks personnel, members of local whale nonprofits and frenzied bystanders, as Monterey Peninsula Engineering provided an excavator to dig a trench to begin the delicate process of moving the live orca. A crane hoisted the animal into the back of a truck, then into a refrigerated van for transport to the Long Marine Lab in Santa Cruz for rehabilitation.

But the animal died en route, leaving many to wonder: What happened?

“It really is just an accidental occurrence that for whatever reason, he ended up [on the beach],” says Dr. Pádraig Duignan, director of pathology at the Marine Mammal Center, who conducted the necropsy. “Once that happened, it was kind of inevitable.”

Test results show the killer whale died from cardiomyopathy, a condition involving stress to the heart. He was determined to be about 2 months old – a healthy young male with no preexisting conditions. He was not malnourished, but somehow, he and the mother got separated. Once stranded, the orca’s body suffered under the force of gravity, which can damage skeletal muscles. This, compounded with difficulty breathing and the stress of separation, proved fatal.

“As well observed as our coast seems to be, nobody has been able to pinpoint which pod he would have come from,” Duignan says. “We don’t even know that, let alone the circumstances around how he ended up on the beach.”

Genetic tests confirm the orca was part of a population known as the West Coast Bigg’s killer whale species, a top predator commonly found along California’s coast feeding on marine mammals. While killer whale species may appear similar, some are far more threatened. Scientists initially considered whether this orca might belong to a pod near Puget Sound that feeds exclusively on salmon – a population whose numbers are dwindling due to a lack of food and exposure to environmental toxins.

“A lot of people seem to think orcas are endangered everywhere. But that’s really not the case,” says Michael Millstein of NOAA, noting that this beached orca is “one of the most successful killer whale species overall.”

Dr. Emily Whitmer, a clinical veterinarian with the Marine Mammal Center who was present both at the scene during the response and in the van during transport, explains that any cetacean (whale, dolphin or porpoise) that strands is in a life-threatening situation and cannot survive out of the water for an extended period.

“This orca calf’s stranding was in a very unusual location,” Whitmer adds. “This is not a common occurrence on the California coastline.”