Bornean orangutan populations have declined by more than 50% over the past 60 years, and the species' habitat has been reduced by at least 55% over the past 20 years.
The Bornean orangutan differs in appearance from the Sumatran orangutan, with a broader face and shorter beard and also slightly darker in color. Three subspecies are recognized, each localized to different parts of the island:
- Northwest Bornean orangutans are the most threatened subspecies. Its habitat has been seriously affected by logging and hunting, and a mere 1,500 individuals or so remain.
Why are they endangered?
Orangutan numbers and distribution have declined rapidly since the middle of the 20th century, due to human activities. These include hunting, unsustainable and often illegal logging, mining, and conversion of forests to agriculture. One particularly catastrophic event was the 1997-98 forest fires in Kalimantan, which killed up to 8,000 individual orangutans.