The Bornean orangutan is the third-heaviest living primate after the two species of gorilla, and the largest truly arboreal (or tree-dwelling) animal alive today.[7] Body weights broadly overlap with the considerably taller Homo sapiens, but that species, of course, is more variable in size.[8] The Sumatran orangutan is similar in size, but is on average marginally lighter in weight.[9][10] A survey of wild orangutans found that males weigh on average 75 kg (165 lb), ranging from 50–100 kg (110–220 lb), and 1.2–1.4 m (3.9–4.6 ft) long; females average 38.5 kg (85 lb), ranging from 30–50 kg (66–110 lb), and 1–1.2 m (3.3–3.9 ft) long.[11][12] While in captivity, orangutans can grow considerably overweight, up to more than 165 kg (364 lb).[13] The heaviest known male orangutan in captivity was an obese male named "Andy", who weighed 204 kg (450 lb) in 1959 when he was 13 years old.[14]
The Bornean orangutan has a distinctive body shape with very long arms that may reach up to 1.5 metres in length. It has a coarse, shaggy, reddish coat[15] and prehensile, grasping hands and feet.[16]