Shot 07/07/2011.## The grizzly bear that attacked and killed a man in Yellowstone National Park acted in defense, park officials said on Thursday, adding that they have no plans to kill the bear.   The female grizzly attacked a hiker and his wife around 11 a.m. Wednesday after the couple surprised the mother with her cubs, they said. The victim, Brian Matayoshi, 57, died at the scene. His wife, Marylyn, escaped the attack without injuries. Park officials were adamant that the bear’s reaction was defensive and that the park does not have plans to track down and kill the bear.##