High Quality Content by WIKIPEDIA articles! Killer whales (or orcas) are powerful predators capable of killing prey much larger than humans, such as leopard seals and great white sharks. They have also been recorded preying on usually terrestrial species such as moose swimming between islands. However, wild orcas are not considered a real threat to humans, as there are few documented cases of wild orcas attacking people, and none of the recorded attacks have been fatal. There have been about two dozen cases of orcas attacking humans since the 1970s, almost exclusively perpetrated by captive animals. Experts are divided as to whether the injuries and deaths caused by captive killer whales have been accidents or deliberate attempts to cause harm.