According to a statement from the Anderson Cabot Center for Ocean Life, during an aerial survey in early March, researchers spotted a single whale swimming about 48 kilometers south of Nantucket, Massachusetts. The animal, which appeared to be on the hunt, dove and resurfaced, allowing scientists on board the plane to film it in action. The experts had a guess as to who they had met, but they weren't entirely sure until they returned to the New England Aquarium.

Scientists admit that for a long time they could not believe their eyes. In recent years, only five gray whales have been spotted in the Atlantic and Mediterranean.

Experts don't know exactly why the whale swam so far north, but they admit climate change may be partly to blame. That's because Canada's Northwest Passage, which connects the Atlantic to the Pacific, has been regularly ice-free in recent years amid global warming.