How often do orcas attack humans?

Captain Robert Falcon Scott witnessed an extraordinary scene during his ill-fated Antarctic expedition when, on Jan. 5, 1911, his photographer Herbert Ponting ran to the edge of an ice floe to photograph a group of orcas that had taken an interest in the expedition dogs tied up on the ice.

“The next moment the whole floe under him and the dogs heaved up and split into fragments,” Scott wrote in his diary. “One could hear the ‘booming’ noise as the whales rose under the ice and struck it with their backs.”