Michael Milstein, a public affairs officer for the West Coast Regional Office of NOAA Fisheries, said that the whale appears to have died after being struck by a ship and that the carcass probably floated ashore. NOAA Fisheries conducted a routine necropsy — an autopsy for animals — on the body to determine cause of death.

“Sperm whales are less common up in the Northwest in the wintertime than they are in the summer, so it’s somewhat unusual to see them here at this time of year,” Milstein said.

About 2,000 sperm whales are thought to live off the West Coast, according to Milstein. The population has not recovered as swiftly as other species after commercial whaling was largely cut off by the mid-1900s, but “they are definitely on the upswing,” he said.

“The last sperm whale hunted and killed off the West Coast was 1971. It really wasn’t that long ago,” he added.

Sperm whales form deep bonds with their family members and travel together for years or even a lifetime, depending on their sex. Females typically stay in the same social unit in tropical waters for their entire lives, while males eventually leave between the ages of 4 and 21 to form “bachelor schools.”

As the males age and grow in size, they begin migrating toward the poles, meaning that bachelor schools shrink in size, with the largest males often traveling alone. Some will return to tropical waters to mate once they have reached their 20s or older, and females only reproduce every few years.

Liz Slooten, a trustee of the New Zealand Whale and Dolphin Trust who has studied the sperm whale as a professor at the University of Otago, said the whale in Oregon may have recently separated from its social unit.

“It looks like a fairly young whale,” she said. “It could be one of these whales that has recently left its pod with its mom and grandma and all the other whales that it knows.”

She said its wounds appeared consistent with “a collision with a very large propeller,” and that evidence gathered from necropsies are often used to make a case for rerouting ships away from whale breeding grounds.

In general, sperm whales face a variety of threats, including strikes with vessels, environmental complications caused by climate change, entanglement in fishing gear and confusion caused by underwater noise pollution.

The global sperm whale population is estimated to have been nearly 2 million in 1710, before large-scale commercial whaling, according to a recent study. It had recovered to about 850,000 in 2022.

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