Animal Info - Kloss' Gibbon
(Other Names: Beeloh, Dwarf Gibbon, Mentawai
Gibbon, Siamang de Kloss,
1. Profile (Picture)
3. Status and Trends (IUCN Status, Countries Where
Currently Found, Population Estimates, History of Distribution, Threats and Reasons
4. Data on Biology and Ecology (Weight, Habitat, Gestation Period, Birth Rate, Diet, Behavior,
Social Organization, Density and Range)
Gibbon #1 (31 Kb JPEG) and Kloss'
Gibbon #2 (15 Kb JPEG) (Gibbon
Kloss' gibbon weighs about 6 kg (13 lb). It lives in tropical rain forest. All
gibbons are arboreal and diurnal. Kloss' gibbon eats mostly fruit and
animal matter. Kloss' gibbon is monogamous.
A single young is born every 2 - 3 years. A group of Mentawai gibbons will "stake
out" a territory in the forest which it
actively defends against other groups of gibbons, to protect an adequate food supply.
Kloss' gibbon occurs on the islands of North and South Pagi, Sipora and Siberut in
the Mentawai group of islands, West Sumatra, Indonesia.
It is threatened by hunting and habitat loss due to deforestation, modernization and
*** An adult male Mentawai gibbon usually sings in the last hour before dawn. He sings
every other day on average, and a song period can last anywhere from 10 minutes up to 2
hours. The male is able to demonstrate his confidence or willingness to defend his territory by the duration and complexity of his song.
Status and Trends
Countries Where Kloss' Gibbon Is Currently Found:
2004: Occurs in Indonesia. (IUCN
[Note: Figures given are for wild populations only.]
History of Distribution:
Kloss' gibbon occurs on the islands of North and South Pagi, Sipora and Siberut
in the Mentawai group, West Sumatra, Indonesia (IUCN 1968). In 1987 it was still thought to occur
on the same islands in the Mentawai chain and, although common locally, it was declining
throughout most of its range.
Threats and Reasons for Decline:
Kloss' gibbon is currently threatened by hunting and habitat loss due to
deforestation, modernization and population growth.
Data on Biology and Ecology
Kloss' gibbon weighs about 6 kg (13 lb).
Kloss' gibbon is found in tropical rain forest.
It is one of the species that live in both the Sundaland
Intl.) and the Sumatran-Nicobar Islands Lowland Forests Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)
7 - 8 months.
A single young is usually born. There are 2 - 3 years between births.
Feeding time usually involves 72% on fruit and 25% on animal matter (Macdonald 1984).
All gibbons are arboreal and diurnal.
Kloss' gibbon is monogamous.
A group of Mentawai gibbons will "stake out" an area in the forest, its home range, which is large enough to provide a
reliable food supply. The group will actively defend the core of this area, its territory, against other groups of gibbons. Conflict
between groups is minimized because the resident male advertises the group's presence by
singing a song to indicate his willingness to defend the group's territory.
Density and Range:
Burton & Pearson 1987, Cons.
Intl., Curry-Lindahl 1972, Fuentes
1997, Gibbon Res. Lab, IUCN 1968, IUCN
1994, IUCN 1996, IUCN
2000, IUCN 2003a, IUCN
2004, Macdonald 1984, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Whittaker
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Last modified: January 7, 2006;