Reclining but alert, a gray Wolf lies in new-fallen snow in the International Wolf Center's live enclosure.

卧著休息却始终保持警惕，“国际狼中心”生态区的一只大灰狼卧在刚下过雪的地上。

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There has been speculation that Knut died from stress relating to three female bears in his enclosure as in captivity polar bears can live to the age of 30.

BBC: Candles by Knut's enclosure