Science Interviews

Non-Vocal Communication in Gorillas

Chris - We as human beings have quite complex patterns of language, but we presumably got this from somewhere. Looking at our next nearest relatives, such as apes and primates, must be a good starting point. What have they told us?

Gilly - Well first of all I'm going to back up a bit and tell you why it's important to look at communication in apes. Firstly, it's interesting because the way great apes communicate with each other may not be the same as how we communicate. Secondly, it may help us place ourselves within the evolutionary process, and see how evolution evolved in humans. As humans, we mainly use vocal signals such as speech. However, we don't use this in isolation. We also have facial expressions, body postures, manual gestures and eye gaze, which are all very important aspects of relaying information.

Chris - Do apes do that too?

Gilly - Absolutely.

Chris - So in the same way that I might wink at you, do apes resort to body language in the same way?

Gilly - They do. Gorillas in particular are non-vocal animals and they do resort to a lot of manual gesture and facial expression to convey information. I'm using this information to see if there are any structures or patterns in the way they communicate with one another.

Kat - What sort of gestures do they use? What means good, or bad?

Gilly - That's an interesting question. At this point, I'm trying not to label anything because I really don't want a subjective component in how I'm looking at how they're relaying information to each other. What I really want to find out is to look at all the modes of communication that they use and code every tiny bit of these actions. I will then run it through some fancy statistics to see if any patterns come out. For instance, if you use a manual gesture consistently with the same facial expression in the same context over a period of time, we might be able to say that that is a gesture.

Chris - Where do we get our gestures from though? I learned a "thumbs up" from people saying to me, 'are you ok?' I then copy. Do the great apes have the capacity to look and see what others do, apply them and copy them?

Gilly - They do but you're opening a big can of worms. There's a big debate over something called ontogenetic ritualisation and social learning. These are the differences between things that are somewhat innate to the species versus things that are learned over time. There have been a lot of studies about how this arises within and between species of great apes. To my knowledge, there is no real certainty.

Kat - Are you just studying one group of gorillas?

Gilly - Currently, yes.

Kat - Because there have been a few studies that have found that groups of animals have regional accents. Some ducks quack in slightly different ways. Do you think that gorillas have regional accents?

Gilly - Definitely, in terms of the way they gesture and communicate with one another. We've already seen from the few papers that have been out that different captive gorillas have different types of gestures within their own groups.

Chris - How do they actually learn these things? Are they pretty good at picking up skills? If you show one gorilla how to do something, does another immediately copy.

Gilly - Again the definition of whether this is social learning or imitation is quite difficult. But I can tell you a little anecdote from the gorillas I work with. They are semi-free-ranging gorillas in that they have an absolutely massive enclosure, and one of the things they have in the enclosure is what they call a honey pot. This is a stable metal device that's permanently there. It has a hole in it and they can choose to pick up a stick and put it into the honey pot every Thursday when it's refilled. They can get this treat out of the honey pot. Two gorillas were taught how to perform this task about twelve years ago by the original keepers. Now the whole family group of thirteen are very proficient at learning this. The youngsters do learn from either imitation or social learning.

December 2005