Sharks! More than 1,000 swarming East Coast, baffling experts

Swarms of up to 1,000-plus basking sharks have been spotted along the northeastern U.S., puzzling experts, according to reports from Fox News and National Geographic.

Here's what we know about the shark swarms so far:

Basking sharks, at 32 feet long, are the world's second-largest fish, and are normally solitary creatures

Aerial surveys have revealed massive groups of them from Nova Scotia to Long Island

Basking sharks spend about 90 percent of their time deep underwater, and only 10 percent at the surface, making any sightings valuable, according to experts

The public can help scientists track sightings with the "Spot a Basking Shark" citizen science program, run by the Pacific Shark Research Center at Moss Landing Marine Laboratories.

Get the full story in this National Geographic report on the sharks and check out our gallery of Great White shark pups below.

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