Communication and Perception
As in all highly social species, communication is varied and complex. Hamadryas baboons utilize visual signals and gestures, vocalizations, and tactile communication. Visual signals include social presenting, in which a females or juveniles display their hind quarters to the male. This submissive signal differs from sexual presenting (which females do to elicit copulation) in that the hindquarters are much lower to the ground. 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. The mouth may be opened during this type of staring, although the canine teeth typically remain covered. Bobbing the head up and down is also considered a threatening behavior among hamadryas baboons. Canine teeth are displayed by a tension yawn, as another threatening gesture. This last behavior is performed only by males toward their rivals or toward predators.
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 these animals 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. All hamadryas baboons, except infants, make rhythmic grunting vocalizations when approaching another animal to signal affiliative intentions. A shrill bark is produced by all except adult males to indicate alarm, especially due to sudden disturbances.
Although chemical communication has not been reported for these animals, anubis baboon females 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 similar olfactory cues may exist in P. hamadryas.
As in all primates, P. hamadryas can spend a significant amount of time engaged in social grooming. Social grooming is thought to help develop and maintain social bonds between animals. Within hamadryas baboons, most social grooming is performed by females and is directed toward the leader of the OMU. Other forms of tactile communication in this species include reassuring touches and embraces, as well as a variety of agonistic bites and slaps.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; acoustic