It's long been a mystery why great white sharks make their annual trip from the rich waters along America's West Coast to an unremarkable patch of water in the middle of the Pacific Ocean.

And although they've known about the area, dubbed The White Shark Cafe, scientists figured it was a 160-mile wide pool of nothing. After all, earlier satellite images painted a picture of the area as largely bereft of life.

But it turns out, there is life in that sprawl of sea — the kind of life white sharks can't say no to.

A research team from Stanford University and Monterey Bay Aquarium visited the site earlier this year and found it flush with "tiny, light-sensitive creatures so tantalizing that the sharks cross the sea en masse to reach them," according to the San Francisco Chronicle.

Every winter and spring, those tiny bits of bioluminescence reach peak percolation, drawing white sharks from their traditional haunts along the coasts of Mexico and the U.S. by the hundreds — making it the biggest known congregation of white sharks in the world.

It isn't clear, however, whether the sharks hit the cafe for the little animals, or the big ones are lured up from the depths by their bright, glowing sheen. But the researchers, using tags to track the sharks, noted that the predators spend their days hovering around the near-black depths — an area called "mid-water" around 1,400 feet below the surface. Then, at night, they swom upward to about 650 feet.

The pattern seems to coincide with the mass upward migration of those beacon-like creatures.

White sharks spend their days at the edge of the pitch-dark depths before rising to about 650 feet below the surface at night. Ramon Carretero/Shutterstock

Part of a mating ritual?

Do great white sharks just like taking a break from apex predator-ing to admire all the pretty lights? Or does mating play a factor here? Researchers did note that male sharks form V-shaped formations as often as 140 times in a single day, while the females maintain their usual dives.

Or is this all an elaborate production to draw out their dinner?

During the expedition, researchers also found a surprising stockpile of squid and tuna in the murky mid-water, a popular snack among great whites.

"Either they are eating something different or this is related in some way to their mating," Dr. Salvador Jorgensen of Monterey Bay Aquarium told the Chronicle. (In the video below, you can see Jorgensen’s presentation about how his team tracked white sharks to this particular ocean desert in the Pacific Ocean.)

Maybe these notoriously solitary creatures just enjoy the company of like-minded sharks now and then in this unlikely cafe culture.

"The story of the white shark tells you that this area is vitally important in ways we never knew about," Jorgensen told the newspaper. "They are telling us this incredible story about the mid-water, and there is this whole secret life that we need to know about."

While white sharks remain confoundedly enigmatic animals — researchers are still puzzling over exactly what they're doing at the Great White Cafe — but it at least offers us one sweet detail.

They can't refuse a good bioluminescent latte among friends.