A rare right whale dolphin washed up on the Oregon coast last week, marking only the fourth time in more than 20 years one of the creatures has been spotted along the Northern Oregon coastline.

On Friday, the animal, a 5-foot-long female, was found at Manzanita Beach and staff from Nehalem Bay State Park quickly reported the beached cetacean to the Marine Mammal Stranding Network, a group that works to save stranded animals and learn how and why they became stranded.

Despite being identified in the 1800s, lIttle is known about right whale dolphins, so named for their resemblance to right whales. They look like a cross between an orca and a bottlenose dolphin, usually sporting black skin with a white stripe on their bottom sides, and they are highly social, sometimes travelling in groups of up to 2,000.

They range all across the North Pacific, as far east as Japan and from Alaska in the north to Baja California in the south. It's unclear what, if any, migratory pattern they follow and there is no estimate for their global population, though experts think there are roughly 14,000 of them swimming off the North American coast.

Globally, the right whale dolphin's primary threat comes from high-sea drift nets, which hang like virtual walls in the water, sometimes 10-miles wide at depths of up to 50 feet. These nets, which were unregulated until recently, catch anything that swims into them, including right whale dolphins.

Experts say these nets are responsible for a 24 to 73 percent population decline in right whale dolphins. In Oregon and California, fishing outfits are now required to use pinging devices, which warn unwitting cetaceans to the presence of the nets.

On June 9th, 2018 a 5.5 foot female northern right whale dolphin (Lissodelphis borealis) washed ashore on Manzanita... Posted by Seaside Aquarium on Wednesday, June 13, 2018

It was unclear what killed the creature discovered in Oregon. The animal was taken to Portland State University for a necropsy, but the results were inconclusive. More tests were being run to see if experts could pin down an exact cause of death.

-- Kale Williams

kwilliams@oregonian.com

503-294-4048