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Scientists were shocked when a sperm whale decided to investigate their remotely operated underwater vehicle (ROV) 1,962 feet below the surface of the ocean. Oceanographer Robert Ballard and his team were exploring the Gulf of Mexico for E/V Nautilus, an expedition to map the Galapagos Rift and gain a better understanding of how life develops around hydrothermal vents on the ocean floor. While looking through the eyes of ROV Hercules, they received a major surprise. A video uploaded Tuesday captured the deep-sea encounter:

"What the heck is that?" one of the scientists exclaimed. It was a sperm whale getting up close and personal. "Encounters between sperm whales and ROVs are incredibly rare," the organization wrote on its YouTube page. Sperm whales, which can grow to be nearly 60 feet long, are an endangered species.

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Amazing moment! Highlight video of a curious sperm whale checking out our ROV! http://t.co/QRRP2hpwMO #nautiluslive pic.twitter.com/CuTXgSpneB — E/V Nautilus (@EVNautilus) April 15, 2015

— Keith Wagstaff