It was obvious from its condition that it hadn't climbed up there on its own - it was quite dead, with parts of its guts hanging out. The question was, what predator had put it up there and where was it now?
After about 10 minutes of waiting near the tree, a member of our party finally spotted something. There was a leopard hiding in some tall grass and bushes about 50 yards away! See if you can spot it in this picture. You can click on the picture for a slightly larger view - it might be helpful.
Here's a zoom in on the picture. Unfortunately, given the grass obscuring the view, this was the best picture I could get. I need to get more practice using the manual focus on my camera. As it was, my camera kept focusing on the grass in the foreground, so the face is a bit blurry.
I found the whole situation quite chilling. I imagined what it would have felt like to be walking along these plains and suddenly discover that face staring back out at me. Or worse, walk past and not notice and become its next victim.