SUSTAINABILITY AND THE ENVIRONMENT
Dr Marina Davila-Ross with microphone and tape recorder during her early orangutan studies .
pocket of jungle and are thought to have been isolated from other Sumatran orangutans about 3.5 million years ago , most likely during a period of volcanic activity .
“ Hunting , small population size and geographic isolation had already raised a particularly high conservation concern , and now there was the hydro dam proposal that would have further reduced their domain ,” Dr Davila-Ross explains .
However , as a result of the research showing the Tapanuli orangutans are a separate species , the dam has been put on hold while further research is undertaken on ways to protect and secure the population .
Dr Davila-Ross says had it not been for the research identifying the Tapanuli orangutans ’ uniqueness , there would be a dam and power station being built right now , placing extreme pressure on the apes ’ long-term survival .
Her role in the species ’ discovery drew on her earlier recordings of the orangutans and matching the acoustic patterns of male ‘ long calls ’ to different population groups .
While her research since has spanned many animal groups , she finds orangutan acoustics particularly fascinating . The adult males are able to produce two sounds at the same time – a rare trait known as biphonation . Dr Davila-Ross measures these with a sonogram that shows audio frequency on a Y-axis and duration on the X-axis .
“ You can see distinct shapes in these long calls and the different durations ,” she says . “ They consist of roars and ‘ huitus ’ in the middle of the call … I call them huitus because I don ’ t know how else to describe the sound . It ’ s a call with bubbling sounds and sighs at the beginning and the end of the call … that description is a rough structure of an orangutan long call .”
Tracing the origins of laughter In her research into great ape communication , Dr Davila-Ross has also studied the evolution of laughter and smiles for apes and humans . “ I developed a phylogenetic ( evolutionary reconstruction ) approach to test whether laughter is a pre-human trait by asking great ape keepers to tickle the apes . The recordings that I obtained of their ‘ laugh vocalisations ’, as well as human laughter , were phylogenetically measured and we were able to conclude they have the same evolutionary origin .
“ In fact , we can say laughter is a pre-human form of communication going back at least 13 million years .”
However , Dr Davila-Ross says a major difference between ape ‘ laughter ’ and human laughter is that
PHOTO COURTESY : DR MARINA DAVILA-ROSS
apes only use this form of expression in a positive context . They don ’ t have different forms , such as ironic or cruel laughter , that humans can express . For apes it is also only inwardly directed from something they are doing , not something they are seeing .
“ Apes don ’ t ‘ laugh ’ when they see something funny . It has to be something they are doing .”
For Dr Davila-Ross this is a fascinating distinction requiring further research into the possible evolutionary reasons : “ Plus you cannot study laughter without considering facial expression , in particular smiles . Where do they come from ? Are they from primordial positive expressions , or fear grins as is more generally believed ?”
For the moment , these are mysteries , but they still form part of her quest to better understand animal communication , which fits with her overarching involvement in conservation .
In particular , Dr Davila-Ross is concerned with improving the rehabilitation of orphaned or injured apes back into the wild and methods through which to better know when an animal is ready .
“ We work with rehabilitation centres to develop approaches that help them more reliably identify candidates for release . Rehabilitated animals face a lot of challenges and knowing when an animal is ready isn ’ t straightforward ; [ it ’ s about ] being able to recognise , for example , what skills an individual still might need to work on , if it is to survive in the wild .
“ You are dealing with individuals from diverse backgrounds and experience . Some have been orphaned by really horrible events ; some might have been pets . You have to understand these differences and work with them individually to prepare them for release .
“ I am passionate about conservation and have always wanted to contribute in some way . Our research and the data we ’ ve been collecting for many years is helping this crucial work being done by rehabilitation centres to sustain the populations of these wonderful animals that are in our care .”
I am passionate about conservation and have always wanted to contribute in some way . Our research and the data we ’ ve been collecting for many years is helping this crucial work being done by rehabilitation centres to sustain the populations of these wonderful animals that are in our care .
– Dr Marina Davila-Ross
ISSUE 03 / 2021