These shadowy images are snapshots from a short film that shows a sperm whale stealing black cod from a fishing ship’s long line by tugging at one end until the fish comes off at the other.

The film is part of a study from Scripps Institution of Oceanography, San Diego, and is published in the Journal of the Acoustical Society of America.

In the video, the whale’s clicking can be heard quite clearly, and it is this, rather than any sneaky fish-nicking, that the scientists were interested in.

“The sounds can be louder than a firecracker,” said Aaron Thode, Scripps researcher. “But until this video recording was made, scientists had not been able to get a measurement of the size of the animal’s head and the foraging sounds at the same time.” (Press release)

Watch it for yourself, and try to work out if it’s real, or just shadow puppetry.