Primates are, without doubt, the most intelligent mammals there are. Their brain, especially in chimps, orangutans and gorillas, is big and really developed. They also have a wide range of facial expressions, which are quite similar to human expressions, and they use the five senses in their totality.
The two main communication forms that primates use though are: visual communication and vocal communication.
In regard to visual communication, we should mention that primates in general have good sight, and that they use it to communicate to each other in the distance. They do this through postures, gestures, and movements. For example, a gorilla can tell another he is comfortable with his presence just by lying down, or can press his lips to show he's uncomfortable and in an aggressive mood. This posture or gesture will be noticed through sight.
Regarding vocal communication, we should mention that, even though their sight is good, primates usually communicate through distance by auditive signs. They do this through different sounds, which vary from species to species. They can make warning shouts, or scream for help, when a predator is near, or even sounds of joy or invitations to play (among the youngsters).
Needless to say, these non-verbal ways of communicating that primates possess, follow certain functions that are parallel to humans' - according to British linguistic Deirdre Wilson - such as recognizing an individual's status, inquiring about aliment, imitating, controlling behavior, keeping contact, recognizing an individual, inviting to hunt or to play, or threatening someone, among others.
Because of their communicative skills and their complex social organization forms, we could say that primates are really intelligent creatures in the animal kingdom. They are social, skillful, and imitative beings, and they're really close to man in the phylogenetic scale. All these facts have made many scientists wonder if such smart animals can learn the human language.
Well, the answer is no. At least regarding the verbal language, as their oral physiology doesn't allow them to produce speech sounds. Men's attempts at teaching chimps, orangutans, and gorillas to talk have all failed, then, but they have also been scientific achievements - since now we know their larynx is really different from humans'.
Another reason why primates cannot talk is their brain; it doesn't contain the Broca and Wernicke areas, which are essential to speak. They would need even more elaborate brains to perform this human skill then.
As an alternative, many researchers have tried to teach primates to use sign language. Primates are plantigrades, and have prehensile hands, with five fingers in each, including opposable thumbs. In short, they are the perfect subjects for the experiment.
The most famous cases have been the ones with Washoe the chimpanzee, and Koko the gorilla. Both animals learnt a great number of signs and linguistic combinations (around 160), which they used daily with their carers and trainers. Therefore, they actually managed to communicate with people through a common language. In spite of this, their linguistic behavior was 100 percent conditioned by the present time, ergo, it was defined by the here and now, as their messages were always about petitions for interaction, games, and food. We could say, then, that even though they stablished a communication with humans, it is not probable that they understood human language itself.
Thereupon, the question on animal communication is still open. We don't know for sure yet which are the neurological and psychological mechanisms that are found in primate communication. Their communication systems consist of a complicated combination of circumstances, learning, and genetic disposition. Studies on the matter, then, must continue.
Originally posted on The Dragon Whisperer.