These Ecologists Borrowed Tricks From Astrophysicists to Count Endangered Orangutans

The thermal-imaging expertise of astronomers helped researchers find the great apes in the hot, humid jungles of Borneo

Thermal Orangutan

In the last century, orangutan numbers have dropped dramatically. The primate’s total on the island of Borneo is down from roughly 230,000 to about 104,000 individuals, while only 7,500 remain on the Indonesian island of Sumatra.

When it comes to critically endangered species, however, rough estimates aren’t good enough to help ensure their survival. That’s why an unlikely combo of ecologists and astrophysicists has teamed up to use cutting edge drone technology to try and count the animals from the sky.

In a video from WWF UK, primatologist Serge Wich from Liverpool John Moores University explains that counting orangutans is a slow and costly endeavor. Typically, researchers trek through the forest, counting nests and deriving population estimates from their observations.

In their latest project, Wich and astro-ecologist Claire Burke, also of Liverpool John Moores University, tested a new approach. They outfitted a drone with the same type of thermal imaging camera used by astronomers to look at the stars to see if they could spot the heat signatures of orangutans and their nests.

Over the course of six days, the team—which also included members of the WWF and orangutan conservation group HUTAN—conducted 28 10-minute drone flights at the Sepilok Orangutan Rehabilitation Centre and the Kinabatangan Orangutan Conservation Project in the heavily forested Malaysian state of Sabah. In total, the drone crew found 41 orangutans in the trees, all of which were confirmed by observers on the ground. They recently presented their work at the British Ecological Society’s Unifying Tropical Ecology Conference in Edinburgh, Scotland.

Because the tropical forests of Sabah are so hot and humid, the team was uncertain whether the thermal imaging would be able to distinguish between the apes and the background environment at all. Yessenia Funes at Earther reports that the team found the system wasn’t very reliable during the day, but worked well before 9 a.m. and after 7 p.m. when the air temperature is cool enough to differentiate from the apes’ body heat.

Burke tells Funes that previous tries to track tropical animals using thermal cameras just couldn’t get a fine enough resolution to work. The more finely tuned instruments used by astrophysicists, however, were able to give usable pictures.

“In thermal images, animals shine in a similar way to stars and galaxies, so we used techniques from astronomy to detect and distinguish them,” she says in a press release. “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.”

Orangutans weren’t the only species caught on camera. The drones also picked up on a troop of proboscis monkeys and a group of pygmy elephants. In previous tests, the team also used the drone to track Mexican spider monkeys and rabbits in South Africa. Next, they will next try to find critically endangered Lac Alaotra bamboo lemurs in Madagascar. Eventually, they want their thermal drones to keep tabs on all sorts of animals.

“Rhinos, elephants—you name it, we want to do it,” Burke tells Funes.

The goal is to create a system in which an algorithm can identify the thermal fingerprint of individual species. “In the future, we hope to be able to track, distinguish and monitor large numbers of different species of animals in real time, all around the globe, so that this technology can be used to make a real impact on conservation and stop poaching before it happens,” Burke says in the release.

This is not the only way drones are revolutionizing ecology. Drones are being used to collect samples from plumes shot out of whale blowholes; estimate numbers of nesting birds, seals; and turtles and to monitor things like land use change and deforestation.

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