They're called Natives and they're not used for anything yet. Right now, you can challenge yourself and try to make as many as you can happy at once. You add them to your population by constructing a hut and placing them in one, after which you must have them regularly fed. You can feed them foods as basic as apples, or prepare entire apple pies for them. The totem pole doesn't do anything to their happiness yet, nor does putting cute, little hats on them.
I think the creators have plans to make them useful for the future, but we probably need to wait until this game gets out of pre-pre-pre-alpha.