RN summer series, part 3: Elephants talk low down

Saturday 12 January 2013 3:45PM (view full episode)

Elephant communication consists of a much wider repertoire than previously known, with significant vocalisations expressed at such low frequencies they are inaudible to the human ear.

First broadcast 13/3/2010

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Maria Zijlstra: G’day!

 It’s not just the human species that’s fascinating, when it comes to communication. Others are too, with elephants displaying a wide repertoire of vocalisations – much more than just trumpeting! – as discussed in this  Lingua Franca, first broadcast back in 2010.


Now, observing animals' behavioural repertoires in the wild, while sitting in a hut or on the top of a four-wheel drive with a pair of binoculars and a notepad, has been the backbone of zoological research, but today's gizmos such as GPS or Global Positioning Systems monitoring, coupled with improved sound-recording techniques, are augmenting previously gained knowledge, off the back of which we can gain greater depths of understanding of some behaviours, such as communication, that are so fascinating particularly amongst the more social creatures, apart from Homo sapiens, such as whales and gibbons and elephants, the topic for this Lingua Franca.

Matt Anderson is currently acting director of behavioural biology at San Diego Zoo's Institute for Conservation Research, studying animal communication or bioacoustics, to use the lingo, and he's been concentrating in particular on trying to understand the vocabulary used by the African elephants in that zoological setting. And I should mention that the breeding herd there includes five young ones between the ages of just a couple of weeks and five years. And while trumpeting is probably what we all think of at first in relation to elephant-speak, it's that other distinctive vocalisation, the rumble, that deep growling noise that they make that's turning out to be so very interesting. Right Dr Anderson?

Matt Anderson: Yes, it's been quite well looked at in the past and is thought to have evolved over time as a long-distance communicator. So, females coming into oestrus will be able to announce to males who aren't part of the herd that they're coming into the breeding season. Classically the elephant biology is such that upon sexual maturity the males go off on their own, so they can often be miles away. So the evolution and development of this low frequency call, the rumble, which also has very long wavelengths, can allow them to communicate over long distances.

More recently the work we've been doing here has been most exciting because we've been hearing these rumbles as well within our zoological setting, obviously over shorter distances, but they're still using these rumbles a lot, and this is what got me interested in looking a bit further.

Maria Zijlstra: So your studies into that rumble has uncovered that it's actually quite a complex communication, and especially given it's infrasound, those lower frequencies that we humans can't hear, what have you found out about the kind of information that these infrasounds contain?

Matt Anderson: This is an interesting field, and elephants, in common with just a few other animals, are able to produce these infrasonic calls. What we hear when we hear the rumble is about two-thirds of the actual vocalisation itself. There's another lower portion, so-called infrasound, that falls lower than we can actually perceive or hear with our human hearing, and it's that section there that appears to be most fruitful in terms of the communication. And we can only really delve into that by using very sensitive microphones and recording these vocalisations and then lastly coming back to the laboratory to use audio-analysis equipment in order to get a handle on what's really going on in those lower portions that we can't actually hear.

Maria Zijlstra: So if you change the playback speed, are they made audible for the human ear then?

Matt Anderson: Yes, it's quite well established that you can manipulate frequencies of sound by changing the playback speed, and in the case of elephants playing them back about three times faster than the normal rate will push all those low frequencies into a realm of our hearing. It does sound rather peculiar to start with.

Maria Zijlstra: I was going to ask, what does it sound like?

Matt Anderson: It's not such a low growl anymore, it's kind of approaching a low to a medium humming noise, because in playback it comes across a bit faster. The interesting thing is it's not just that you're playing it back faster but you actually are hearing more information, so that's why it sounds different as well, because you're actually being able to perceive these lower frequencies within your realm of hearing.

Maria Zijlstra: And I understand that what you've been doing is taking visual footage of your elephants and then correlating it, like putting together all the imagery with when the sounds are made, and then watching the behavioural results, seeing what the communications are. In other words, understanding what Mum says to Junior by looking at the behavioural response.

Matt Anderson: Right. So what we were doing initially when we first got into looking at the infrasound within these calls and potential different meanings to these rumbles is recording opportunistically. So it would be myself and some colleagues out there with a microphone and a digital recorder to try and get an idea about this so-called vocabulary. And the way you do that is whenever they make these sounds or utter these calls, you see what they're doing and it gives you a behavioural context and thus a meaning.

So what we did then was we designed some collars, they're made out of a thick leather material, with pouches, one that sites between the ears at the top of the head which has a GPS unit, and then one that falls below the chin which is our audio recorder. They're on most of our herd now, they're just on for a 24-hour period, they're not on these animals all of the time. We're first to be able to put them on during a 24-hour period within a zoological setting, which is exciting. And what we're interested in doing there is using the GPS feed to tell us where that elephant is, who they're interacting or hanging out with the most and indeed what they're saying to one another during those times. So it gives us a map, both night and day, as to what the herd's up to and what's going on.

Maria Zijlstra: So what have you found out?

Matt Anderson: There's strong evidence from our studies to suggest they are manipulating or changing some of the elements of that low frequency part of the rumble, and it seems to relate not only to pecking order or rank. The elephant herds, as I mentioned, are predominantly mature females with offspring, male and female, and the males don't leave the herd until they mature, and in those situations there is a hierarchy, it is a matriarch, there's a queen bee, the head of the herd, usually an older female, and then there's closely related individual females that fall down the rank in a subordinate sense.

We're starting to get a handle on the fact that some are more vocal than others and if you're vying for a position above your station at the moment then you do tend to be a lot more verbal. There's a lot of communication going on with this which is very interesting to us.

Maria Zijlstra: Are there particular kinds of communications or vocalisations or sentences that you can tell in detail are being communicated? Can you tell from the responses that the other animals are giving to those vocalisations?

Matt Anderson: Yes, I think one of the most interesting findings that we're looking at is with mothers-to-be. As you know, elephants have a very long gestation period, just under a couple of years, and towards the end of that they seem to have a certain type of rumble call where they're manipulating certainly some of the lower frequency stuff that we can't hear to announce to the herd that the baby is imminent.

You can imagine that this might be useful for several different reasons, but certainly within the last 10 to 15 days of this very long gestation or pregnancy period, we think letting the rest of the herd know has evolved in order to avoid against predation. It might seem odd that we're talking about predation of these enormous creatures, babies are in the realm of 300-pounds heavy, you wouldn't think there was necessarily a problem, but a group of hyenas or some lions can be problematic, and they are a bit shaky on their legs for the first couple of days.

What we've seen, in answer to your question, is that on emitting this particular type of rumble call the mum is telling the rest of the herd that the baby's coming, and they do react in quite a specific manner often during this time. The rest of the herd is seen to form a ring all facing outwards, and presumably in the wild that's where the calf would be sequestered so as to avoid issues of predation.

Maria Zijlstra: So can we assume then that those infrasounds in those rumbles on those occasions, they're not just inaudible to the human ear but also to hyenas and lions, for example, because otherwise it would be a dead giveaway, wouldn't it.

Matt Anderson: Yes, so that would be the assumption, absolutely. We're doing some work with some other species where that seems to be the case as well where if you had a newborn calf, say...it's quite an unusual animal, the okapi, they also use infrasound, and we think that that's so as the new mum can keep an eye on her calf, or an ear, if you like, without the predators hearing. And we think that's certainly part of the attribute that's been going on with the elephant.

Maria Zijlstra: Might it be a bonding thing also, so it's a kind of a communication, a sharing, so that everybody is mindful of what's happening here with us?

Matt Anderson: That's potentially the case. We're obviously thinking along those lines too, and I think that in elephant societies they do spend an awfully long amount of time together, and I think those relationships are much more complex than we first anticipated, and this is basically being voiced by members of the elephant community within our herd.

Maria Zijlstra: I'm really interested, and I wonder if you might be able to answer this; when I watch human beings, and other beings too, communicating with each other in family groups in particular, the adults have a different kind of way of talking to the young ones, and I wonder whether with these elephants in these matriarchal herds, particularly when there are young ones about, as there are in your zoo in San Diego, do they vocalise differently like humans to their young than they do with each other, with the adults of the species and, if so, how does that differ?

Matt Anderson: We're not absolutely sure on exactly if there's marked differences in that regard. Certainly they do tend to rumble in different manners to one another in terms of the pecking order, and those rumbles seem to different in terms of the infrasonic portion, in terms of how they're relating or talking to the youngsters, absolutely. But beyond that they're some of the most pertinent questions that we're yet to answer, so I'll have to get back to you on that.

Maria Zijlstra: So it is possible, then, that they do have a kind of a baby-talk, a kind of a sweetie-talk that they do with the babies, with the little ones?

Matt Anderson: It's possible, yes. Whether we can say that absolutely at the moment...I think that there's such complexity involved with this social situation that I wouldn't be at all surprised if there are different vocalisations or different manipulations in relation to how they react to youngsters.

Maria Zijlstra: Yes, although as a human the mind boggles as to how you do higher-pitched coochie-coo talk in such a deep rumble.

Matt Anderson: Right, yes, I think that maybe it will differ in terms of that, absolutely, but I think that there's probably some of this information or friendly communication, for want of a better phrase, that's hidden to us right now. We're just digging into that right now using the software and so on.

Maria Zijlstra: And any idea whether what you've discovered is the same for Asian elephants as for African elephants?

Matt Anderson: I suspect there are some similarities given that the herd dynamics are similar through both and so on. But the minutia or the fine details of the infrasonic communication will have to be looked at in some depth in the Asian elephants. So I wouldn't want to speak out of turn but there do qualitatively or just to the ear at the moment seem to be some similarities, yes.

Maria Zijlstra: Finally, how might this information be useful for your conservation work of African elephants in Botswana, for example?

Matt Anderson: Absolutely. We're very excited at the moment that this might be applicable to some human-elephant conflict situations, such as when elephants go into crop areas, they traditionally would be...in the worst case scenario they would be killed by the farmers because they want to save their crop. We may be able to have some playback mechanism where we broadcast certain words or phrases within the rumble that the elephants don't care for and it makes them move on rather than going through the crop. It could be a nice elegant subtle approach to being able to increase our chances of elephant conservation in that manner.

Maria Zijlstra: Thank you very much for your time and best wishes to you and your elephant herd.

Matt Anderson: My pleasure.

Maria Zijlstra: On the phone from the San Diego Zoo Institute for Conservation Research in California, the Director of Behavioural Biology there, Dr Matt Anderson. And you can click through from the webpage for this program at the Lingua Franca website, to find out more, if you like! At abc.net.au/radio national, and then just scroll through the program bar to find LinFra. 

Next week, the fascinating story of the name that this continent/island/country that we now call ‘Straya, once had – in a limited form and so just on some maps – ‘Ulimaroa’ – and how that came about.


Dr Matt Anderson,
acting director of behavioural biology at the San Diego Zoo Institute for Conservation Research.


Maria Zijlstra
Sound Engineer
Tim Symonds

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