SEATTLE (AP) — It's a good thing seals aren't on a humpback whale's menu.

A photograph by a whale-watching naturalist captured a seemingly bewildered seal in the mouth of a humpback whale after the giant marine mammal accidentally gulped it last Thursday in the waters off Anacortes, Washington.

The food mix-up began while a Blue Kingdom Whale and Wildfire Tours boat spotted birds flying over a school of fish and a humpback whale swimming toward it, Captain Tyler McKeen said. He said the humpback then used a lunging feeding technique, where the whale opens its mouth wide and takes in small fish and water. But instead of remaining underwater afterward to filter through its baleen, it surfaced and began opening and closing its mouth.

After the whale went back underwater, photographs and videos were checked by whale watchers.

“It only took a couple seconds for everybody to pull up the frames and zoom in,” McKeen said. “That’s when we saw the seal. It was a funny, funny moment for everybody. I mean, it probably wasn’t that funny for the seal.”

A photograph by Brooke Casanova shows the seal, which presumably was also hunting the fish, emerging from the bottom of the whale's mouth. McKeen recorded a phone video where the seal is getting flushed out.

“I’m guessing that this situation probably happens every once in a while just because there’s lots of other stuff that eat these fish too,” McKeen said.

Humpback whales visit the Salish Sea, the inland waters between British Columbia and Washington state, during their migrations. Humpback whales were hunted to local extinction in these waters, but over the last 25 years, their numbers have recovered and are now routinely seen in whale-watching tours, McKeen said.

He added the whale that accidentally gulped the seal is known as “Big Mama" because she has been seen with seven different calves over the years.