Scientists were baffled as to why a load of sharks rock up to a 'white shark cafe' in the Pacific every year - but now we finally have an answer.
So, the 'white shark café' is an area in the Pacific Ocean between Hawaii and Baja California where white sharks gather in huge numbers during migration.
But here's the kicker: for a while, nobody knew why they gathered there.
Thom Maughan, a software engineer at the Monterey Bay Aquarium Research Institute in Moss Landing, California, studied the occurrence, and was amazed by it.
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He said: "It's as if it got a sniff, like it smelled something, and started chasing after it.
"The question is, are they chasing food, or are they mating?"
The expert and his colleagues worked with Salvador Jorgensen of the same aquarium to design a shark-mounted video camera to try and uncover this long-standing aquatic mystery.
Jorgensen said: "I think of it like Burning Man. You have all these Bay Area white sharks, and every year they head out into this white shark café, out into the desert of the ocean—and we’re not exactly sure what they’re doing out there."
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Even stranger, once they got there the sharks started diving to depths of up to 1,400 feet up to 120 times a day. What were they up to?
Well, Jorgensen teamed up with Stanford University marine biologist Barbara Block to tag the sharks to better observe their behaviour at the cafe.
It turns out they were there to feed on light-sensitive animals like squid and phytoplanton.
Jorgensen told SFGate: "It’s the largest migration of animals on Earth—a vertical migration that’s timed with the light cycle.
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“During the day they go just below where there is light and at night they come up nearer the surface to warmer, more productive waters under the cover of darkness."
There are still some unknowns. Females don't engage in the same diving behaviour as males, and scientists still don't understand why.
This could be related to mating, or they could be eating something different.
Block told NPR: "The male white shark and the female white shark are doing completely different things, and that's not something we've seen so much before.
"We have to spend some time studying these behaviours to try to understand if this is courtship behaviour or is this really a feeding or foraging behaviour."
Joshua Nair