Preening is a behavior typical of what kind of animals?

I'm pretty sure humans preen!

PC, my initial thought was that monkeys comb through each others hair, so I clicked mammals, luckily I had a second chance to guess.

PC, we do, our hair, our use of body lotion and shaving. I, for one, engage in mutual preening. You scratch my back, I scratch yours. Gets rid of dead skin cells.