Critically Endangered Orangutan Populations Face Decline
World Orangutan Day, observed on August 19, draws attention to the critical status of the three orangutan species—Sumatran, Bornean, and Tapanuli—all classified as Critically Endangered by the International Union for Conservation of Nature (IUCN).
Recent assessments indicate that the Sumatran orangutan population stands at approximately 11,694 individuals, while the Tapanuli orangutan population is estimated at 716. These figures represent a combined decline of 19.5% since 2011, equating to an annual decrease of about 1.8%.
The Bornean orangutan, divided into three subspecies, also faces significant threats. Current population estimates suggest there are roughly 6,300 in the northwest, 97,000 in the southwest, and 24,800 in the northeast of Borneo. All subspecies are critically endangered.
In addition to habitat loss and human encroachment, climate events pose an extra threat to these species. A study published in June 2026 reported that extreme rainfall in November 2025 led to landslides in Batang Toru, resulting in the loss of approximately 58 Tapanuli orangutans, or about 11% of their population.