SEASIDE, Ore. – It wasn’t a good weekend for two mammals on the northern Oregon coast – a seal and a sea lion both washed up with what appear to be major shark bites from a great white, aquarium officials said.

Seaside Aquarium photo

The seal's bite wound.

On Friday, a dead harbor seal drifted onto the beach at Seaside with a two-foot chunk taken out of its back. And since Saturday, an extremely unhappy California Sea Lion has been resting on a beach with a sizable wound.

In both cases, officials believe it was a shark -- likely a great white shark – that attacked.

SLIDESHOW: Photos of wounds (Warning: Graphic)

"It could have been an orca," said Keith Chandler with the Seaside Aquarium, "but it's more likely a shark. A killer whale would likely mess the thing up a lot more, or eat the whole thing."

The harbor seal with a gaping hole in its back was a full-grown adult, probably about six years old, officials said.

"They often swim upside down, so they probably weren't paying attention when the shark came down on it," Chandler said. "I've never seen a hole that big in a seal."

"The entire backbone is gone," said Tiffany Boothe, with the aquarium and the Marine Mammal Stranding Network.

Meanwhile, a full-grown sea lion has been nursing itself on a beach with a shark bite in lower back.

"It's one disgruntled sea lion," Chandler said. "I couldn't get too close to look at the wound 'cause it threatened to bite me."

The tear is mostly in the sea lion’s fur, where some of the flesh was torn. It’s about one foot wide and very infected.

"It's oozing a lot of green," Chandler said.

Some great whites do wander around the waters off Oregon, but not too many, according to Boothe. She believes warmer water this summer brought more sharks closer to shore.