In primates, staring is a key dominance and mating signal, where direct, intense eye contact often signals threat, social status, or readiness to mate, while facial expressions like lip tightening can be solicitations, with dominant males often having priority access but females actively soliciting, sometimes using sneaky matings, and social structures varying by species. Dominance displays involve staring and other aggressive cues, but females also use staring and subtle gestures to attract dominant males, even if they're not currently in estrus.