How do chimpanzees communicate?
Scientists who study chimpanzees know that they have forms of communication that are complex and diverse, and they still surprise them frequently.
All chimpanzees use a set of vocalizations or sounds and facial expressions to exchange information with one or more individuals, who must interpret them to get the intended information.
Chimpanzees produce more than 30 different vocalizations which use in contexts like feeding, sexual activity, social interaction, and alarm, making them stand out among other animals for the use of their sounds. Common chimpanzees emit more than 15 types of calls, which sound different and have different meanings, which only a few are known.
Here are some of the sounds emitted for communication purposes:
– When the Common chimpanzees are excited, they utter a kind of prolonged shouting known as “pant-hoot,” which at first is tenuous and sounds like “hoo .” The screams increase in volume, and at some point, they are almost like barking until finalizing again with the “hoo.”
The males of higher rank are the greatest emitters of pant-hoot, but each chimpanzee can utter his own.
– A typical alarm call consists of loud cries, screams, and howls that are heard about 2 miles away. The other members of the community recognize who issued the sound.
Common chimpanzees emit more than 15 types of calls with different meanings.
– When seeing snakes, Pan troglodytes utters a tonal barking.
– Subordinated common chimpanzees emit a mixture of grunting and panting to higher-ranking individuals.
– When common chimpanzees hunt, they emit a brief barking.
– Bonobo females have a characteristic scream, but the males apparently have a slightly wider repertory, which includes grunts, barks, and “pan-hoots.” Barking is an alarm call.
– When a bonobo finds a food source, he sends a particular sound to inform his companions that food is available there.
Groups of chimpanzees have two types of calls:
a) calls issued between individuals in the same group, and
b) remote calls, emitted by someone far away.
Can you recognize a dog in a good mood just by looking at its face? Confusing, right? However, this is not difficult in the case of chimpanzees. Through years of research and observations, a set of facial expressions is recognized that indicate a state or emotion such as fear, aggressiveness, submission and worry. The ability to express feelings through facial gestures appears early in young chimpanzees.
If you see a chimpanzee fully discovering his teeth until showing the gums, he is not smiling. In fact, this gesture indicates that he is frightened. If he moves its lips together and joins them forming an “o” while frowning and raising its chin slightly, he is terrified. When he open his mouth with a little smile, he may be showing submission, and if he frowns and touches his jaw with one hand, then might be worried.
In both species, some movements and attitudes are similar to those that humans make in similar contexts. So, these primates have been seen to hug and kiss, tickle, touch their hands, clean their bodies and throw stones. Young bonobos have an adorable demeanor: they make funny gestures playing (well, at least is what it seems to us).
Common chimpanzees give threatening signals to others when they hit the ground, raise their arms or look directly. Shaking or trampling branches is interpreted as a courting signal to a female. During threatening displays, they tend to compress the lips, and if they are suffering, they bring the edges of their mouth down, just like a human child.
A typical alarm call is heard up to 2 km away.
Do they understand human language?
Some chimpanzees have been trained in captivity to learn some types of human language. They have been able to learn and express words using the sign language and the use of geometric symbols (lexigrams) using a computer. Some have shown an incredible development because they have the ability to use familiar symbols to describe new objects to them and to understand human speech to some extent. However, so far only a few have been able to communicate with people, and it does not appear that they could learn to speak or communicate in an even more complex human form.
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