Communication and Perception
As in all highly social species, communication is varied and complex. Yellow 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 reveals the lighter fur in the area of the eyelid, and is an aggressive gesture. Canine tooth display through a tension yawn is another threatening gesture. It can be directed toward a rival male, a predator, or 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 retreating from high-tension situations use rapid glances to break tension. An adult male who is guarding sometimes sit with his 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.
Vocalizations made by yellow 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. Adult male yellow baboons make grunting vocalizations as a threat. Screeching is common during aggressive encounters, and can be made by any age or sex class. Subadult and adult yellow 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. Rhythmic grunting may be produced by all yellow baboons except infants when they wish to signal amicable intentions to another animal. Finally, adult and subadult yellow baboons of both sexes are known to produce a dog-like bark when they become separated from the main part of the troop.
Tactile communciation 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 yellow baboons. 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. Because there is considerable hybridization between anubis baboons and yellow baboons, and because the Ibean form of yellow baboons may have arizen originally through hybridization between typical yellow baboons and anubis baboons, it would be interesting to examine various yellow baboon populations for production of aliphatic acids.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; acoustic