The middle of the Bornean jungle is not the ideal place to study for your Masters degree unless that is you are researching some of the world’s most elusive mammals.
Working around rapids, dense jungle and fearsome predators, University of Queensland student Sunny Sanderson has applied a unique way of examining the variations between different species of gibbon – their call.
“In the areas where I’m working it’s very difficult to access things, whether it is permits or food or resources so I decided to use vocalisations as an inexpensive, non-invasive means of sampling gibbon populations in Indonesian Borneo,” she said.
“Ideally I would do a genetic study but that is quite often out of reach.”
In 1999 while completing her Bachelor of Arts, Ms Sanderson received a UQ scholarship to study in Indonesia. During this time she volunteered as a translator for an orangutan research station, which sparked her interest in primates. She then returned to UQ to complete a Bachelor of Science degree.
Ms Sanderson is currently studying a Master of Philosophy with the School of Integrative Biology under the supervision of Associate Professor Anne Goldizen, looking at the variations in calls between gibbons in Borneo in order to determine where they are hybridising and the impact of this on the gibbon population.
Gibbons are medium-sized arboreal primates that live throughout the rainforests of South East Asia in family groups.
“This research allows us to consider questions about speciation. If these are truly different species then how is it that they can be interbreeding?” she said.
“It is believed the calls the gibbons make are a pre-mate isolating mechanism, so I am looking at the effect of altered call structures on hybrid groups.”
Every morning the female gibbons make a Great Call as part of a duet with their mates to re-establish their pair bonds and their territory.
“The male and female will start whooping, then the female will do a few notes to silence the male and then she does her Great Call, which starts with a few introductory notes,” Ms Sanderson said.
“Then she peaks and gets quite vigorous until she reaches her climax and then after that the male does a few notes and they go on like this for about half an hour every morning.”
The climax portion of the call is used to determine the species. Different species of gibbon are separated geographically across South East Asia. In Borneo there are two species that have been hybridising: the Bornean Gibbon and the Agile Gibbon.
“The female Agile Gibbon will do between six and 15 notes over 20 seconds whereas the Bornean Gibbon does between 50 and 96 notes over a shorter period of time, so it is very easy to pick out the differences between hybrids and pure species,” she said.
The only other study in this region to have examined these calls was conducted about 20 years ago.
Working in the geographical centre of Borneo, it takes between three and five days to get to the base camp using a variety of transportation including light planes, motorised boats and then small canoes.
The University of Cambridge runs the camp and Ms Sanderson is assisted by four Indonesian field assistants. She is one of the few foreign researchers to have had the opportunity to work in the area.
During her fieldwork Ms Sanderson gets up at 3am, has a quick breakfast and is then off in the canoe in the dark to a listening point.
“The male will do a pre-dawn solo so I use the male to locate the family group,” she said.
“Then it is a matter of getting under the group as quickly and as quietly as you can without them knowing you are there.”
Once the female starts her call Ms Sanderson records the sound. She is looking at variation in the calls and therefore travels to a range of different sites throughout central Borneo.
“To get to different sites can be difficult because there are a lot of rapids,” she said.
“I have two people with me but we can only carry enough supplies for two weeks at a time.
“We carry our boats around the rapids, hike in and then set up camp in the forest.
“Every day when I get to a new site I can tell what sounds interesting because generally on one side of the river you will have the pure species and on the other side you will have the hybrid zone.”
Ms Sanderson is currently back in Australia analysing the recordings of the calls.
Media: For more information, contact Sunny Sanderson (mobile 0422 962 334, telephone 07 3217 8595) or Chris Saxby at UQ Communications (telephone 07 3365 2479, email c.saxby@uq.edu.au).
