Lions and tigers and bears, oh my!

Wild animals have broken loose from their cages. The human caretaker is found dead of as yet unstated causes. Schools are closed and there's a sort of self-imposed curfew after dark 'cos no one knows what's lurking around the corner looking for an easy meal. Sounds like the plot of Rise of the Planet of the Apes. Or maybe Madagascar. If it's the latter, I'd keep an eye out for the penguins.

Edit 01:
Oh, crap! It was funny before, but I didn't expect this story to end in a massacre! :'(