A ration of fruit and vegetables for an orangutan in Borneo

The number of orangutans is declining dramatically. Between 1999 and 2015 alone, more than 100,000 animals disappeared (Voigt et al. 2018). This led the International Union for Conservation of Nature (IUCN) to upgrade the Bornean orangutan to a "critically endangered species" on its Red List in 2016 (Ancrenaz et al. 2016). The main reason for this dramatic development is the deforestation of the rainforest, which today forms the habitat for the remaining almost 54,000 orangutans. Between 1973 and 2010, the population was decimated by 56%. 39% of the former habitat has disappeared irrevocably. This corresponds to an area larger than Portugal. The rainforest is being cleared for palm oil plantations, timber and mining. The size of the plantations alone grew from 6,000 km² in 1985 to 140,000 km² in 2015 (WWF 2017).

Orangutans do not live in large social groups. Only mother and child stay together for up to eight years. If mother and child are separated, this causes a dramatic disruption in the development of the babies. A baby orangutan can easily become a victim of animal traffickers. Many of the animals are sold on the black market and kept privately as pets, although keeping, selling or killing them is strictly prohibited in Indonesia (White, Lanjouw, and Rainer 2015; Voigt et al. 2018).