The Tapanuli orangutan (Pongo tapanuliensis) is a species of great ape endemic to the Indonesian island of Sumatra. It is the most recently discovered species of great ape, and the rarest, with only about 800 individuals still living.
After decades of being overlooked, the Tapanuli orangutan was listed as a distinct species in 2017, making it the most endangered species of great ape in the world. Unfortunately, this newfound status has yet to bring the Tapanuli any reprieve from the threats that are endangering its existence. As its native habitat continues to shrink due to deforestation, the Tapanuli is pushed ever closer to extinction.
The Tapanuli orangutan is endemic to the Batang Toru Ecosystem in North Sumatra, Indonesia. Its habitat is located in the three contiguous districts of South Tapanuli, Central Tapanuli, and North Tapanuli, consisting of lowland and montane. Lowland forest types are characterized by flat terrain and consist of tropical rainforest and tropical peat swamp forest.
Montane forests are characterized by steep terrain and often contain mountain species. As forests are cleared for logging and agricultural development, the orangutan’s habitat is being destroyed, depriving the species of its natural resources and habitats.
The Tapanuli orangutan is the smallest of the great apes and has the most slender build. Its long arms and legs, combined with its long reddish-brown fur and flattened face, give it a distinctive appearance. The Tapanuli orangutan is the smallest of the three species of great ape (Borneo, Sumatran), with males typically reaching a height of around 4 feet (1.2 meters) and weighing between 75 and 100 pounds (34 to 45 kilograms).
Females are even smaller, usually reaching a height of 3.5 feet (1.1 meters) and weighing between 50 and 70 pounds (23 to 32 kilograms). This small size is thought to be a result of the Tapanuli’s isolated habitat, which has allowed it to exist in relative isolation from the other great apes for thousands of years.
With such a limited gene pool, the Tapanuli has become physically distinct from the other species, with its small stature being one of the most telling signs. Despite their diminutive size, Tapanuli orangutans are among the strongest of the great apes and can easily lift objects much larger than themselves.
This strength allows them to build nests in the treetops, where they sleep and breed. Breeding is an essential part of the Tapanuli orangutan’s life cycle, as females only reproduce once every seven to eight years. To ensure that the species survives, it is essential that the Tapanuli orangutan has sufficient habitat and resources to build nests and reproduce.
In the wild, orangutans are solitary animals, only meeting with other orangutans to breed. Females reach sexual maturity around 12-13 years old and give birth to a single infant every 8-9 years, making the Tapanuli one of the slowest reproducing species of great ape.
Males reach sexual maturity around 15-16 years of age and are known for their prolonged courtship. To attract a female, males will make loud calls, or long calls, that can be heard up to three miles away. Unfortunately, this slow reproductive rate, combined with their already-small population size, has made it difficult for the Tapanuli to rebound from the threats posed by deforestation and habitat destruction.
Conservation efforts for the Tapanuli orangutan have been underway in recent years, with a variety of organizations working to protect their habitat and raise awareness of their plight. In 2018, the Indonesian government established the Batang Toru Ecosystem Management Unit (TEMU), which is tasked with managing and restoring the Tapanuli’s natural habitats.
Additionally, the International Union for Conservation of Nature (IUCN) has set up a conservation center where orangutans can be monitored, protected, and rehabilitated when needed. The United Nations has created the ‘Great Apes Survival Project’ in an effort to protect the Tapanuli orangutan and other endangered species of great ape. Despite these efforts, the Tapanuli orangutan is still in danger of extinction due to deforestation and poaching.