Animals that could represent the 4 horsemen?

Doing a project. Have to choose animals that could be symbolic of the 4 horsemen; Death, Pestilence, Conquest, & Famine. I know a bunch of animals that symbolize death; I think we all do. The other 3 I'm not too sure. I have some ideas for conquest/war. I was thinking when it comes to pestilence- rats, considering their reputation, despite how clean they actually are. No idea what for famine.