Communication and Perception
As in all highly social species, communication is varied and complex. Chacma baboons utilize visual signals and gestures, vocalizations, and tactile communication.
Visual signals include social presenting, in which a female or juvenile displays its hind quarters to a male. It can also be done by a female who has approached another female with her black infant. This submissive signal differs from sexual presenting (which females do to elicit copulation), and is often accompanied by lip smacking. Staring is a threat behavior, the effect of which is enhanced by the differently colored fur in the region of the eye which is revealed when the baboon stares. Eyebrow raising is a similar aggressive gesture. Canine tooth display through a tension yawn is another threatening gesture. It is performed by lower-raking males toward higher-ranking males who are consorting with estrus females or who possess meat. Male baboons who are close to one another can use tooth grinding to threaten one another. Baboons who are being threatened use rapid glances in the opposite direction to break tension. Adult males who are guarding mates sometimes sit with their erect penis is plain view. This penile display communicates the male’s presence to other males.
Teeth chattering and lipsmacking, although not technically vocalizations, are auditory cues of reassurance, often performed by a dominant animal when another is presenting to him. A female may also lipsmack when approaching a mother and her black infant.
Vocalizations made by chacma baboons include a two-phase bark, or "wahoo" call, which adult males direct toward feline predators or toward other males. It is thought to communicate the presence of the male and his arousal. This call may be preceded by grunting, a soft threat call. Screeching is common during aggressive encounters, and can be made by any age or sex class. It appears to inhibit aggression. Subadult and adult baboons produce a yakking call when retreating from a threatening animal. This call is often accompanied by a grimace of fear. A shrill bark is produced by all except adult males to indicate alarm, especially due to sudden disturbances. Finally, rhythmic grunting may be produced by all chacma baboons except infants when they wish to signal reassurance to another animal.
Juveniles and infants produce some vocalizations unique to their age class. These include chattering, which is a nasal, grunt-like call emited during play. They also produce an ick-ooer sound which communicates a low level of distress.
Adult females of this species produce a vocalization during copulation called a muffled growl. The mouth is closed, and the cheeks expand and contract during this call.
Tactile communication is common in cercopithecines. Social grooming is used to reinforce social bonds, as well as to remove parasites and debris from the fur. Social mounting is a reassurance behavior. Anubis baboons also perform a friendly nose-to-nose greeting.
Chemical communication has not been reported for this species. However, female anubis baboons are known to produce aliphatic acids when they are sexually receptive. These acids are thought to enhance a female’s sexual attractiveness. It is possible that female chacma baboons also produce these acids.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic