My granddaughter and I took a trip to the zoo earlier this month. Here are a few of the shots I took using a Canon 7D and a Canon 100-400.
Oscelot - 1/125s f/5.6 at 310.0mm iso400
Timber wolf with an attitude - 1/800s f/5.0 at 190.0mm iso400
One of the new gorillas - 1/100s f/5.6 at 400.0mm iso400
Here are a couple of shots taken by my granddaughter with a Canon 30D and a Canon 70-300IS.
Polar Bear - 1/500s f/5.6 at 275.0mm iso400
Mandarin Duck - 1/1000s f/5.6 at 300.0mm iso40