Thinking, with a stick

I was bored yesterday so I hopped a military airlift to the mountains of Rwanda and stalked wild mountain gorillas for a while.

OK, so that's a lie; I went to the Woodland Park zoo in Seattle with my wife and baby daughter. The gorillas were impressive. This one was hanging out looking pensive, while holding a stick. Not sure what the stick was for; possibly, to beat off other gorillas that would interrupt the ruminating.