On September the 18^th a severely injured male Tapanuli orangutan was found on a plantation at the edge of the Batang Toru forest. The orangutan was taken in by the North Sumatra Natural Resources Conservation Agency (BKSDA North Sumatra) and the Orangutan Information Centre (OIC), who took him to receive treatment from the Sumatran Orangutan Conservation Programme (SOCP).

The head of the OIC told Mongobay that the injuries included a gash on his head, and a large stab wound under his left armpit, both of which were infested with maggots. He emphasised that these injuries were caused by humans, stating “Our team suspects that the wounds were caused by sharp weapons. If the injuries were a result of the orangutan fighting with other animals, then there should be scratch wounds, not stab wounds”. Orangutans are often considered as pests by local farmers, which can cause these vicious attacks when the animals venture out of the forest.

 The severely injured Tapanuli orangutan pictured with a gash on his head. Image: OIC. 

This orangutan is the first of the Tapanuli species we know to have been found in this condition, and this may be the start of more deadly encounters with humans as their habitat and food sources are depleted further by the Batang Toru dam and its associated infrastructure. Orangutans have extremely low reproductive rates, which means that if over 1% of the population (in this case only a few individuals per year) are killed, it will likely cause population collapse.

Scientists are particularly concerned about female Tapanuli orangutans, as they tend to stick to their home range even if their rainforest is lost. This exposes them to conflict with local people, risk of starvation and dehydration and increases the chance of their young being captured for the illegal pet trade.

Responders assess the orangutan's injuries. Image: OIC. 

Unfortunately, the injuries this orangutan sustained whilst fleeing the dam project are unlikely to be an isolated incident as forest clearing and building work continues. This is why the Ape Alliance, alongside the IUCN, are calling for an immediate moratorium on the project. With such small populations and slow breeding rates, every individual orangutan impacted by the dam is dangerous for population viability. The Tapanuli orangutan was discovered to be a distinct species by scientists in 2017, making it the newest, and also most endangered species of great ape.

The species may well be the first great ape to become extinct within modern history. If this comes to pass it would violate a number of commitments made by the Indonesian government, including the Indonesian Law Regarding the Conservation of Biological Resources and Ecosystems (Law No. 5/1990), and the Aichi targets. Therefore, it is important for the Indonesian government to take the warnings from experts seriously.

As well as the imminent threat from the Batang Toru hydroelectric project, the Tapanuli orangutan is threatened by loss of habitat, hunting, human-orangutan conflict, an expanding goldmine, and logging concessions. These factors exacerbate in the face of expanding infrastructure and decreases the barriers between human and orangutan populations, which is likely to lead to more incidents such as this one.

  Article by Ape Alliance coordinator Iona Haines.