PROBOSCIS MONKEY FACTS
Brought to you by Mindy's Memory Primate Sanctuary. If you find this page useful please consider making a donation to help us continue to care for needy monkeys.
| Family: Cercopithecidae |
Subfamily: Colobinae |
| Genus: Nasalis |
Species: larvatus (Note: The other species in this genus, concolor, the pig-tailed langur, is included in the langur section. The proboscis monkey, due to its distinct characterisics, gets its own page. |
Appearance:
Coloration - top of head, back, and backs of limbs are reddish-orange; shoulders, cheeks, throat, and nape are pale orange; legs, underside of trunk, rump patch, and tail are whitish grey to light orange; faces are naked - pink in adults, but dark blue in infants. At birth the infants' fur is almost black.
The males have long, pendulous noses - this is the origin of their name. These normally droop down beyond mouth, but will inflate and turn reddish when they are excited. Their scrotums are black and penises, when aroused, are bright red and highly visible.
There is pronouned sexual dimorphism - average weight for males is 47lbs; for females 22lbs. Females also have much smaller, up-tilted, noses. All have obvious pot bellies - the typical specialized, divided stomach of the colobines, but the proboscis has the largest stomach of them all. They have rather long fur, and large ischial callosities. The second and third toes are webbed together.
Range and Diet:
Proboscis monkeys are only found on the island of Borneo, where they sometimes compete with long-tailed macaques and orangutans for food. They inhabit coastal nipa palm, mangrove, lowland, riverine, and peat swamp forests. Their diet is primarily leaves, but they also eat seeds, fruit, flowers, and animal prey.
Behavior and Social Structure:
Proboscis monkeys are diurnal and arboreal. They move quadrupedally and also make great leaps from tree to tree. They live in variable social groups - in harems or bachelor troops, and one group may join with a larger community at times. They are not known to be territorial, and home ranges will overlap quite a bit. Either males or females will emigrate. Some allomothering has been seen.
These monkeys are good swimmers and will use this skill to escape dangerous situations. Males will give a honking alarm call when they sense danger. They are said to make "distinctive braying calls" (Sleeper, 106) at morning and evening.
Reproduction and Lifespan:
Males are sexually mature from 60-80 months; females from 36-60 months. Gestation is 166 days; birth interval 12-24 months. Their average life span is 13.5 years.
Conservation Status:
Endangered (USESA.) Habitat loss continues to occur.
Interesting Facts:
If need be, proboscis monkeys can swim underwater for about 66 feet.
Proboscis monkeys, as their name suggests, have the largest noses of any primate.
There has been no obvious biological reason found for the male's big nose. It may help resonate their loud calls. One theory put forth is sexual selection - the females prefer males with big noses.
Proboscis monkeys have been very difficult to keep alive in captivity, probably due to their highly specialized dietary needs.
Current Research with Proboscis Monkeys:
(Note: The following are examples of recent research done with these primates, it is by no means an exhaustive list. This list will be periodically updated as more information becomes available. Also, though Mindy's Memory Primate Sanctuary DOES NOT support invasive medical research on primates, some articles of this type will be listed - both for information and as examples of the work that is currently being done with these animals.)
Anonymous
Proboscis monkeys caught - many die. IPPL NEWS 27(1): 3-5, 1999.
Anonymous
Stop press - KSBK report on proboscis disaster. IPPL NEWS 27(1): 6-8, 1999.
Proboscis Monkey Websites (with photos):
References:
Primate Information Center. , Manager. . Washington Regional Primate Research Center and the Health Sciences Libraries. University of Washington, Seattle
Rowe N (1996) The Pictorial Guide to the Living Primates. East Hampton: Pogonias Press
Sleeper B (1997) Primates. San Francisco: Chronicle Books
