Originally posted by Kzar:

Remember that raids always target YOU first, and structures and animals second if they can't see them.

Tell that to the trolls I was actively pounding on who insisted on going after my boars instead. I don't think this was always the case, because they did seem to try to get to me first when I first started playing, but ever since they reworked how raid mobs target players, this seems to have changed. They consistently go after my tames first, which makes me guess they go after whatever they're closest to in terms of aggro.