Scientists conducting marine research in the Gulf of Mexico say they got some unexpected company when a curious sperm whale made several passes by their robotic underwater camera.

The video footage was captured by an expedition investigating the seafloor of the gulf for methane seeps, using a remotely operated vehicle, or ROV, dubbed Hercules.

As the vehicle went about its business of observing methane bubbles and taking seawater samples around 1,900 feet below the ocean surface, cameras caught the sperm whale making several "laps" around it, researchers with the Nautilus Live expedition said.

"It was such an amazing moment," said expedition spokeswoman Susan Poulton onboard the Nautilus ship controlling the Hercules. "There was a lot of cheering on the ship."

The encounter took place at a depth that is relatively shallow for sperm whales, which regularly dive into the deepest ocean abysses in search of squid prey.

The whale came close enough for scientists aboard the 210-foot researcher ship to see scars on its nose that may have been caused by a boat's propellers.

The video, which quickly went viral when it was posted on the expedition's Facebook page, was captured April 15 off the coast of Louisiana.

Sperm whales, which can grow to 70 feet in length, are on the International Union for the Conservation of Nature's red list as a "vulnerable" species.

They are considered highly intelligent and, at least in the case of animal starring in the viral video, are apparently curious as well.

There have been previous incidents in which sperm whales have approached underwater ROVs for a better look.

Although the whale made several close passes around the 11-foot-long, 5,400-pound underwater vehicle, there was no contact, Poulton said.

"He spent 15 minutes circling and examining the ROV and was at one point eye-to-eye with the equipment," Poulton said. "Shockingly, he didn't even tap the vehicle."

There is some question about whether "he" is a he or a she, the expedition scientists said; without a whale expert aboard, they contacted researchers onshore in the hopes they could examine the video and determine if the animal, estimated at about 35 feet long, was male or female.

Nautilus Live will continue to stream live video of its research activities over the coming months, which can be viewed online at NautilusLive.org.

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