Non-Human Primate Communication: A Brief Sketch

Even non-human primates live in complex societies and need to frequently communicate with each other. They communicate with smells, sounds, visual messages, touching, and rely heavily on body language. Typically, they communicate present emotional moods and intentions, focusing on the immediate. Discreteness refers to the ability to differentiate or separate individual spoken words within a sentence -not blending them together. The oral sounds of some apes and monkeys are somewhat discrete at times as well. Though primatologists have observed some communication patterns commonly used by primate species, unlike us, their communication does not involve much displacement. That is, they apparently do not “talk” about things too far removed from recent or immediate experiences. People discuss Alexander the Great and Ben Franklin. There is no evidence that non-human primates do this.

Can other primates learn and use human languages or have the ability to comprehend a symbolic communication system and to use it creatively? Research on these questions has been ongoing since the 1960’s. It is now clear that at least the great apes can learn and use a simplified version of sign language. However, there’s no universal agreement upon the limits of how innovative their use of language is. It seems sparse, with an upwards limit of about 500 words. One of the stars in this research has been a male bonobo named Kanzi. Check these clips out and make up your own mind about how well he uses language.
Odors, vocalizations, gestures, and facial expressions are used to inform others of their psychological state and present concerns, which is an important clue to what they are likely to do next. In the picture above, the outstretched hand and pleading facial expression directed toward another troop member are obvious indications of this chimpanzee’s appeal for sharing. It also probably reflects and reinforces his lower position of dominance hierarchy within the community.

Prosimians have excellent olfactory abilities and usually use body odors to communicate.  Male lemurs regularly mark their woodland territories with chemicals produced by scent glands in their wrists; similar to dogs, wolves, and cats marking their territories with urine. In both cases, the scent is recognized as a personal signature. Tamarins and marmosets also use scented urine to mark the gum trees that are important food sources in their territories. In all of these species, scent marking is a way of claiming territory and warding off intruders.

Most primate species use threatening gestures, stares, and poses to intimidate. This is usually sufficient to prevent physical fighting, which is rare. The dominant male can usually prevent major conflicts and keep order by using subtle displays. Baboons flash their eyelids, or open their mouths in a way that looks like yawning. Marmosets and tamarins cannot change facial expressions too much, so they chirp repeatedly and turn around to show their genitals from behind. My girlfriend left me for doing that.

Most primates communicate affection and reduce group tension by sitting close to each other, touching, and mutually grooming. Grooming is used for communication and reinforcing different bonds. Chimpanzees even have grooming sessions that go for hours when an old acquaintance rejoins the community. It also calms emotions following outbursts by adult males. Members seem to enjoy grooming infants and sometimes compete for the opportunity.

The physical act of grooming clearly carries social and psychological benefits, as it does for humans just as a parent brushing a child’s hair, or a partner running their fingers through your hair has benefits. Some primates, including humans, will even “groom” other species of animals (think dogs and kittens). Among non-human primates, inter-species grooming occurs when they are in captivity and deprived of the opportunity to groom their own kind. They are even known to groom people. However, it does not seem to be a pattern of wild non-human primates.