"There have been very few confirmed attacks on humans by wild killer whales, none of which has been fatal.[125] In one instance, killer whales tried to tip ice floes on which a dog team and photographer of the Terra Nova Expedition was standing.[126] There is speculation that the barking of the sled dogs may have sounded enough like seal calls to trigger the killer whale's hunting curiosity. In the 1970s, a surfer in California was bitten, and in 2005 a boy in Alaska who was splashing in a region frequented by harbour seals was bumped by a killer whale that apparently misidentified him as prey.[127] Unlike wild killer whales, captive killer whales are reported to have made nearly two dozen attacks on humans since the 1970s, some of which have been fatal.[128] [129]"