Can pets read human emotions?

My cat can definitely sense my emotions. She is often very aloof, but the several times she's seen me cry, she actually approaches and will rub against me and sometimes even lick me. It seems like she knows when I need her to be loving, because when I'm acting normal, she'll usually act annoyed when I pet her, but if I'm sad, she encourages it, pushes her head against my hand to make me keep going. (: I think that the fact that animals can't speak makes them even more receptive to raw emotion, because it does not take language to understand.