Bornean orangutans build beds with pillows and hold leafy umbrellas in the rain
Each night a Bornean orangutan weaves a fresh nest from branches, sometimes adding a roof, a pillow and a blanket of leaves. Youngsters learn the craft by watching their mothers. The same apes swat bees with leafy twigs, scratch their backs with sticks and carry bunches of branches overhead like umbrellas.
The only great apes native to Asia, orangutans on Borneo are the biggest of the three Pongo species and the largest ape that truly lives in trees. Wild males average about 75 kilograms, females about 38.5, and arms can span 1.5 metres from shoulder to fingertip. Mature males grow fatty cheek pads called flanges and a large throat sac; one obese captive male named Andy weighed 204 kilograms in 1959. The genus name comes from mpongo, a Bantu word for a large primate first applied to chimpanzees.
Their menu includes more than 400 foods, from wild figs and durian to bark, honey, fungi, bird eggs and insects, and some have even snatched live fish from the water. They occasionally eat soil, perhaps to neutralise toxins in plant food, and rarely prey on slow lorises. More solitary than Sumatran orangutans, they also travel on the ground more often, possibly because Borneo has no tigers.
Family life runs slowly. Females first give birth around 14 or 15, infants cling to their mother's belly hair through the first year, weaning comes at about four, and full independence arrives near seven. Adults live 35 to 45 years in the wild and about 60 in captivity. Bornean and Sumatran orangutans split roughly 400,000 years ago but were treated as one species until DNA sequencing separated them in 1996.
About 104,700 remain in the wild, far more than the fewer than 14,000 Sumatran orangutans, yet the species is critically endangered and numbers are below 14 percent of historic levels, falling mostly in recent decades. Logging, oil palm plantations and hunting drive the decline, and infants taken for the pet trade usually mean a dead mother. A find of around 50 animals in South Kalimantan in 2014, where none had been recorded, offered a rare surprise.
Source: Bornean orangutan
