A Humpback Whale breaching in the Stellwagen Bank National Marine Sanctuary. The purpose of breaching is unknown. It may be a form of communication, a method of stunning fish prey, or a way to remove parasites from the skin. In this behaviour, up to 90% of the animal's body clears the surface of the water, and a vertical speed of 29 km/h is reached.Photo credit: Whit Welles