Why, you call 911 of course. I imagine it would be a challenge for the 911 operator not to laugh out loud, but it was true...
My favourite part is the elephant who didn't particularly notice they'd escaped and went to sleep just outside the pen. She's the one at the far left not being sprayed with the hose.
Update: The National Post provides this delightful picture, and links to the 911 call and dispatcher conversation. "Outstanding elephant" indeed. And what a nice police department to host the mp3s - not all would.