Baboons

Baboons have a complex system of communication that includes vocalizations, facial expressions, posturing, and gesturing. These vocalizations, which baboons use to express emotions, include grunts, lip-smacking, screams, and alarm calls. The intensity of the emotion is conveyed by repetition of the sounds in association with other forms of communication.

Baboons communicate with each other primarily through body gestures and facial expressions. The most noticeable facial expression is an open-mouth threat where the baboon bares the canine teeth. Preceding this may be an eyelid signal, raising the eyebrows and showing the whites of the eyes, that is used to show displeasure. If a baboon really becomes aggressive, the hair may also stand on end, threatening sounds will be made, and the ground will be slapped.

In response to aggressive facial expressions and body gestures, other baboons usually exhibit submissive gestures. A fear-face, a response to aggression, involves pulling the mouth back in what looks like a wide grin.

Presenting among baboons takes place in both sexual and nonsexual contexts. A female will approach a male and turn her rump for him to show that she is receptive. This type of presentation can lead to mating or to a special relationship between the pair. A female may present in the same way to an infant to let the infant know it may come close to her. She may use this body gesture as a simple greeting to a male, indicating that she respects his position. A female will also present to another female when she want to fondle the other female's infant. Males present to other males as a greeting signal. Their tails, however, are not raised as high as those of females when they present.

Presentation is also used as an invitation or request for grooming, and for protection. Baboons freely engage in embracing to show affection to infants and juveniles. The frontal embrace has also been seen as a gesture of reassurance between baboons when they are upset. Infants have their own forms of communication that involves a looping kind of walk, wrestling, and a play-face. The play-face is an open mouth gesture they use to try to bite one another.