Blog 1: Bornean Orangutan

     The Bornean Orangutan (Pongo pygmaeus) is a fascinating species of primate. Bornean Orangutans belong to the suborder Haplorrhine, infraorder Simiiformes, superfamily Anthropoidea, family Hominidae, genus Pongo, and species pygmaeus. Some scholars place the Bornean Orangutan into the family Pongidae instead of Hominidae because of its differences from humans. The Bornean Orangutan also includes the subspecies pygmaeus, morio, and wurmbii. These subspecies are the Northwestern Bornean Orangutan, the Southwest Bornean Orangutan, and the Northeast Bornean Orangutan respectively. Bornean Orangutans have red/orange hair covering their bodies. Bornean Orangutans have very long arms and broad shoulders because they are arboreal and move through suspensory locomotion. Males often have a “face disk” or highly pronounced jowls called flanges. These flanges are used to attract mates. Males stand about a meter tall and weigh around 60-90kg. Female Bornean Orangutans are smaller at 75cm tall and weigh 40-50kg. 

    Bornean Orangutans live about 40 years in the wild, and longer in captivity. They remain in the infancy stage for about the first 2.5 years of their life. They are in the juvenile stage of development from 2.5-7 years. The adolescent stage lasts from years 7-10. Male Bornean Orangutans experience a subadult stage from about 10-15 years of age. Female Bornean Orangutans enter adulthood at around 8 years of age, while males are fully adult at around 15 years. Female Orangutans become sexually mature at 7-8 years but often don’t have their first birth until 12-15 years. Gestation lasts anywhere from 230-300 days. Orangutans are not fully weaned from their mothers until 5-8 years of age. 

Bornean Orangutans are currently considered critically endangered with only around 104,00 individuals remaining in the wild. In 1982 a Species Survival Plan was put forth for the Bornean Orangutans. Orangutans are the only living Asian great apes and can only be found on the islands of Borneo and Sumatra. Efforts to protect orangutan habitats from logging and development have been key to protecting this species. 

An Orangutan Foundation International staff member visits with a rescued orangutan. Photos courtesy of OFI.

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Works Cited:

DePalma, Eric. “Bornean Orangutan.” Orangutan Conservancy, 10 Jan. 2025, orangutan.com/orangutan-facts/bornean-orangutan/.

Downey, Kathleen. “Bornean Orangutan, Pongo Pygmaeus: New England Primate Conservancy.” New England Primate Conservancy - ​Committed to Leaving a Legacy of Hope ​and Tools to Build a Better Tomorrow for All the Earth’s Citizens, 6 Nov. 2024, neprimateconservancy.org/bornean-orangutan/.

PERKINS, L. (1998), Conservation and management of orang-utans Pongo pygmaeus ssp1. International Zoo Yearbook, 36: 109-112. https://doi.org/10.1111/j.1748-1090.1998.tb02891.x

San Diego Zoo Wildlife Alliance Library staff. “Libguides: Orangutans (Pongo Spp.) Fact Sheet: Reproduction & Development.” Reproduction & Development - Orangutans (Pongo Spp.) Fact Sheet - LibGuides at International Environment Library Consortium, 20 Aug. 2024, ielc.libguides.com/sdzg/factsheets/orangutans/reproduction.