When I, Stephanie Carmody, first started working at the Elephant Listening Project, I was amazed at how tight-knit everyone seemed to be despite constantly traveling for field work. ELP is a large family, with 5 full time team members, 9 undergraduate analysts, and 6 outreach members. Our Ithaca office ranges from extremely busy, with more people than chairs in a room, to only a handful of workers at a time. This last month has been hectic with most of our members abroad, leaving our Ithaca office quieter. ELP is global with ongoing research projects throughout the year in areas like the Dzanga Bai and Congo. However, when a member returns, there is always a rush of excitement and catching-up to do. Thus, shouts of “Daniela’s back!” were heard throughout the office at the arrival of one of our recent travelers, just back from a National Geographic supported field season in Central African Republic. Postdoctoral Research Associate Daniela Hedwig has been part of the ELP family since 2016 and has contributed largely to our understanding of forest elephant bioacoustics and the functions of their characteristic vocalizations. Though Daniela was interviewed last year (interview found here: https://medium.com/elp-rumbles/daniela-hedwig-on-her-work-in-dzanga-bai-39fd948653b2) , her arrival from the Bai necessitated some catching-up!
The interview was conducted in person, with an audio recording which was translated later into the following dialogue:
Stephanie Carmody (SC): In a previous interview with Gabi Himmel here at ELP, you described Dzanga Bai, where you do much of your research, as being one of the most magical places you’ve ever been; I was curious — what about the Bai makes it so magical?
Daniela Hedwig (DH): It’s just when you go there the first couple of times, even still now, you must imagine that you’re walking through this really dark forest where you’ve got this twilight and a little bit of sun is coming through the canopy but overall, It’s very dark. Then when you climb up the observation platform in the forest suddenly, the sun is shining and it’s bright and your eyes need a little while to adapt and you realize that there are 100 elephants standing there. The place feels like it is made by elephants; we are so used to humans making and changing places, but this place is completely shaped by animals.
SC: The elephants may be hard to see in the forest, but with the acoustic monitoring units at ELP, you’re able to pick up their sounds. Can you describe these vocalizations to people who may not be familiar with elephant noises?
DH: They’re very low frequency, very low sound and often very cozy. These low frequency vocalizations are long and mix. You can still feel them when you are close to the elephant. When they rumble you can feel vibrations; it’s like standing next to a huge tractor.
SC: Is there variety in their vocalizations?
DH: We looked at the structure of the rumbles alone and we were thinking there may be different types of rumbles just based on the structure, but that’s not the case. The rumbles are variable and sometimes they start at a lower frequency and it goes up and then down again. We thought that there were distinct types but there aren’t, it’s all completely integrated and that’s the case with the savanna elephant; so, you have the rumbles and then you have a whole set of loud vocalizations like roars — which is what you mostly hear. The funny thing is that when we walk through the forest towards the clearing you can start hearing the elephants roaring from far away and to me this sounds like I imagine dinosaurs to sound.
SC: That sounds a little scary.
DH: Well it is a little scary and it sounds so powerful but then when you spend time at the clearing, you realize it’s the little elephants that are roaring and making so much noise! That reminds me, there is also a noise called an ‘ayooga’ which is the combination of a roar and rumble. Sometimes it starts with a rumble and then it goes into a roar and sometimes it even ends in a rumble, so they put them together differently.
SC: Since you’ve joined ELP’s team in 2016, have you made any fascinating bioacoustics discoveries?
DH: The most interesting thing was when we tried to better understand the detection distances. We found that forest elephants on average can only hear each other’s rumbles from 800m, that’s the maximum, and this distance is dependent on ambient sound conditions. This is much lower than what the savanna elephants can do — they can hear each other and recognize each other over 2km. That makes you wonder how forest elephants can use vocalizations to maintain their relationships over large distances. With the savanna elephants, they have those really complex social organizations and a fission-fusion society where they split up into smaller groups and they come back again; they’re supposed to do that because they can communicate over large distances, but the forest elephants don’t seem to be able to do that so there must be some implications on how they can maintain their social relationships and maybe that means their social organizations cannot have such a complex organization such as the savanna elephant’s.
SC: Is this difference in sound travel mostly due to the environment that forest elephants live in?
DH: Yes, we found that the forest elephant rumbles have a slightly lower pressure because they are a little bit smaller so they cannot produce such loud vocalizations as the savanna elephant and then it’s also definitely the environment; in the forest where you have all this vegetation, sound attenuates much faster than in the open savanna but then on the other hand, there is also ambient noise in the forest and that masks the elephant rumbles to some point.
SC: You’re getting ready for another trip to Africa soon (this Thursday!), to further continue this research. What’s it like getting ready for another trip and what do you hope to accomplish there?
DH: Well, it’s exciting but also kind of stressful. It shouldn’t be too stressful because I’ve just been there for 3 months, and I’ve left most of my stuff there so not too much crazy packing. I like to be here, and I also really like to be there so it’s happy and sad at the same time. In terms of what we hope to accomplish, we want to continue what we did the last few months in the field, collecting recordings for analysis. So far, we have over 100 hours of vocalizations. When we go to the clearing, we pick one individual and observe that one for an hour and then we switch to someone else that we know and were able to do that for 100 hours now. It sounds like not that much, but it is; it’s really a lot of hard work!
SC: It certainly sounds like a lot of hard work! We’ll let Daniela get back to packing, as everyone at ELP wishes her good luck on her travels!