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They apparently don't like life in a cage – even if it's supposedly environmentally accurate. Hmmm, think CBS' new show “Zoo” could be closer to reality than we think?
Grizzly bear picks up a 50lb rock and tries to smash the glass of his zoo enclosure with repeated blows as startled visitors watch
The animal picked up the rock and slammed onto a pane of glass at the Minnesota Zoo on Monday morning
No one was hurt and the five-layer pane stayed in place 'like a windshield', zoo manager said
Visitor present during incident said rock had to weigh 50 pounds
The grizzly bear exhibit is now temporarily closed
Read more: Grizzly bear shatters barrier with basketball-sized rock at Minnesota Zoo Daily Mail Online