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RARE OBSERVATION IN SUAQ «Otto» is a handsome orangutan male who was first observed in 2008. Full view


The normal eating habits of wild orangutans are well known. They like to eat all kinds of fruits and leaves, and also insects like ants and termites too. Unlike their close relatives the chimpanzees and people, they have only rarely been seen in the past hunting and eating other mammals.

In November 2020, however, two field assistants working for the University of Zurich observed and photographed the large adult male orangutan «Otto» as he captured and then devoured a small nocturnal primate known as a slow loris (Nycticebus coucang). According to Caroline Schuppli, head of Zurich University’s research project SUAQ at Suaq Balimbing, there have been eight observations of orangutans catching and eating slow loris in Suaq since the early 1990s. The orangutan population in Suaq shares this behaviour with orangutans in Ketambe, another research station in Sumatra, near the centre of the Leuser Ecosystem. No orangutans have yet been seen to eat slow loris elsewhere in Sumatra, or in neighbouring Borneo. According to a study from 2012, an explanation for orangutans hunting slow loris is, they do so in phases when food or fruit is scarce.

The behaviour of orangutans in Sumatra can vary from population to population. Suaq orangutans are also known for making and using tools on a regular basis, such as sticks to eat honey from bee’s nests or to get the seeds of the hard and extremely itchy Neesia fruit. This tool utilisation has also not yet been observed in other wild orangutan populations.

> The SUAQ Orangutan Project
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