A trainer at Sea World was killed by a killer whale (Orcinus orca), also known as the orca. While killer whales are not aggressive towards humans in nature, they have been involved in deaths of people in captivity. This is a sad story, but another reminder that whales and dolphins are not pets and should not be kept in captivity.
Here is the story: http://www.cbc.ca/world/story/2010/02/24/killer-whale.html?ref=rss
Giovanni Bearzi from Tethys made a good point on Tethys Blog:
"Why not let orcas kill their own prey in the wild, instead of using these top predators as toys and then be shocked if some of them, sometimes, behave as wild animals?"