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A group of sea lions in Monterey Bay, California were chasing fish alongside a pod of humpback whales when the hunt took an unexpected turn. As a whale hurtled up from the deep to swallow fish near the surface, it nearly swallowed a sea lion in a single gulp.

Wildlife photographer Chase Dekker captured the astounding image while on a whale-watching boat with the tour agency Sanctuary Cruises, and he shared the photo on Facebook and Instagram on July 23.

In the image, the alarmed-looking seal rests on the whale's lower jaw, poised to slide down into its throat. [Beastly Feasts: Amazing Photos of Animals and Their Prey]

However, the seal was spared that gruesome fate. Dekker posted on Facebook that he was "100% confident" that the sea lion escaped, because "the whale kept its mouth wide open as it sank back down into the sea," he wrote.

"Minutes later, the whale was feeding again and I am sure the sea lion was too," Dekker added.

In fact, it would have been physically impossible for the humpback to swallow something as big as a sea lion, which can weigh up to 1,000 pounds (453 kilograms). Humpbacks' throats are just a few inches wide, and can stretch to no more than 15 inches in diameter, National Geographic reported.

At the time the photo was taken, the whales and sea lions were competing for bites of a so-called bait ball. These balls form when groups of small fish (anchovies, in this case) close ranks and swim in a tightly packed sphere, so that fewer vulnerable individuals are exposed to predators, according to Smithsonian Ocean.

Humpback whale's upper jaws are lined with hundreds of baleen plates made of keratin, and the animals feed primarily on tiny crustaceans called krill, small fish and plankton. The animals gulp mouthfuls of food and water — a behavior called lunge feeding — and then the baleen filters out the seawater and traps the food inside the whale's mouth, according to the Woods Hole Oceanographic Institute.

"The sea lions were at the surface and as the whales swam up to lunge feed, all the sea lions jumped out of the way, except one," Dekker said on Facebook. "This sea lion got trapped inside the baleen whale's mouth as it fed, which probably caused a great deal of distress to both parties!"

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