The proboscis monkey (Nasalis larvatus) or long-nosed monkey ...
The proboscis monkey (Nasalis larvatus) or long-nosed monkey, known as the bekantan in Indonesia, is a reddish-brown arboreal Old World monkey that is endemic to the southeast Asian island of Borneo. This species co-exists with the Bornean orangutan.[3] It belongs in the monotypic genus Nasalis, although the pig-tailed langur has traditionally also been included in this genus.[4] The monkey also goes by the Indonesian name monyet belanda ("Dutch monkey"), or even orang belanda ("Dutchman"), as Indonesians remarked that the Dutch colonisers often Proboscis monkeys belong to the Colobinae subfamily of the Old World monkeys. The two subspecies are:[2] N. l. larvatus (Wurmb, 1787), which occupies the whole range of the species N. l. orientalis (Chasen, 1940), restricted to north-east Kalimantan
Reproduction[edit] Females become sexually mature at the age of five years. They experience sexual swelling, which involves the genitals becoming pink or reddened.[14][17] At one site, matings largely take place between February and November, while births occur between March and May.[18] Copulations tend to last for half a minute.[12][14] The male will grab the female by the ankles or torso and mount her from behind.[12] Both sexes will encourage mating, but they are not always successful.[17] When soliciting, both sexes will make pouted faces. In addition, males will sometimes vocalize and females will present their backsides.[11][17][18] Mating pairs are sometimes harassed by subadults.[17] Proboscis monkeys may also engage in mounting with no reproductive purpose, such as playful and same-sex mounting. Gestation usually last 166–200 days or slightly more.[18] Females tend to give birth at night or in the early morning. The mothers then eat the placenta and lick their infants clean.[19] The young begin to eat solid foods at six weeks and are weaned at seven months old. The nose of a young male grows slowly until reaching adulthood. The mother will allow other members of her group to hold her infant.[12][18][19] When a resident male in a one-male group is replaced, the infants are at risk of infanticide.[20]
Reproduction[edit] Females become sexually mature at the age of five years. They experience sexual swelling, which involves the genitals becoming pink or reddened.[14][17] At one site, matings largely take place between February and November, while births occur between March and May.[18] Copulations tend to last for half a minute.[12][14] The male will grab the female by the ankles or torso and mount her from behind.[12] Both sexes will encourage mating, but they are not always successful.[17] When soliciting, both sexes will make pouted faces. In addition, males will sometimes vocalize and females will present their backsides.[11][17][18] Mating pairs are sometimes harassed by subadults.[17] Proboscis monkeys may also engage in mounting with no reproductive purpose, such as playful and same-sex mounting. Gestation usually last 166–200 days or slightly more.[18] Females tend to give birth at night or in the early morning. The mothers then eat the placenta and lick their infants clean.[19] The young begin to eat solid foods at six weeks and are weaned at seven months old. The nose of a young male grows slowly until reaching adulthood. The mother will allow other members of her group to hold her infant.[12][18][19] When a resident male in a one-male group is replaced, the infants are at risk of infanticide.[20]
