Astro-ecology: Counting orangutans using star-spotting technology

11th April 2019

A collaboration between astrophysicists, conservationists and ecologists aims to save rare and endangered animals

A ground-breaking scientific collaboration, partly funded by STFC, is harnessing technology used to study the luminosity of stars, to carry out detailed monitoring of orangutan populations in Borneo.

Liverpool John Moores University, WWF and the HUTAN orangutan conservation programme came together to examine better ways of detecting the great apes in the Bornean forest canopy, by using drones fitted with thermal-imaging cameras.

Orangutans, like all great apes, build a sleeping nest in trees. Traditionally orangutan numbers are estimated by counting these nests from the ground. However, this method is costly and time consuming due to the large areas that need to be surveyed.

“All orangutan species are critically endangered and monitoring their numbers is crucial for their conservation", said Professor Serge Wich, Liverpool John Moores University’s expert in primate behavioural ecology.

By combining drone technology with thermal-imaging cameras, which are usually used by astronomers, researchers were able to spot and classify the animals’ heat signatures. To distinguish the primates from their surroundings, they performed flights before 9am or after 7pm local time.

Dr Claire Burke, an astro-ecologist at the university, said: “We tested the technology on orangutans in the dense tropical rainforest of Sabah in Malaysia. In thermal images, animals shine in a similar way to stars and galaxies, so we used techniques from astronomy to detect and distinguish them. We were not sure at all whether this would work, but with the thermal-infrared camera we could see the orangutans quite clearly because of their body heat, even during fog or at night.

“The biggest difficulties occur when the temperature of the ground is very similar to that of the animal we are trying to detect, so the images from morning or evening flights are more reliable. Absolute surface temperatures cannot be used to differentiate species as animal body temperatures change with that of their environment.”

This innovative technology could potentially be used to understand and monitor population numbers of orangutans or other endangered primate species.

The astro-ecologists are now developing a machine learning algorithm to tell animal species apart, based on their unique thermal fingerprint.

You can learn more here



This research is funded in part by the STFC, WWF-UK and the UKRI Global Challenges Research Fund grant ST/R002673/1 (PIs S. Longmore & S. Wich)

The project will also feature in the BBC Two ‘Equator from the Air’ series later in Spring 2019.

Last updated: 11 April 2019


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