07/07/2015 11:26 BST | Updated 07/07/2015 11:59 BST

Grizzly Bear Smashes Zoo Glass Wall With Basket-Ball Sized Rock

A grizzly bear livened up proceedings at a Minnesota Zoo on Monday – by grabbing a rock and repeatedly smashing it into the glass wall of its enclosure.

The bear – armed with its basketball-sized rock – startled visitors on the other side of the five-layered pane, though no one was hurt.

Zoo animal collections manager Tony Fisher told the Minneapolis Star Tribune the glass stayed in place "like a windshield."

bear smashes wall zoo

A grizzly bear at Minnesota Zoo repeatedly smashed a rock on the five-layer pane of glass in a viewing window

The grizzlies have been relocated to their indoor pens and the area will be closed until a new pane of glass has been installed.

Fisher isn't sure which of the three bears is responsible for busting one of pane's five layers.

But he suspects it was Kenai, a nearly full-grown male who is "usually the clown out there."

grizzly bear

It's not known for certain which of the zoo's bears is responsible for the incident (file picture)