Cloudy days are the best for photographing animals in natural light, but don’t let harsh afternoon sun stop you from trying. You just have to approach it differently. You’re not going to get beautiful evenly lit portraits, but you might get some nice dramatic effects if you can find the right spot.
This kind of thing begs for a black and white treatment. You’re probably already going to be risking blowing out some highlights, so make that work in your favor.
The Zootographer 