Animal Info - Mentawai Gibbon

Animal Info - Kloss' Gibbon

(Other Names: Beeloh, Dwarf Gibbon, Mentawai Gibbon, Siamang de Kloss, Siamang Enano)

Hylobates klossii

Status: Vulnerable

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Weight, Habitat, Gestation Period, Birth Rate, Diet, Behavior, Social Organization, Density and Range)
5. References

Profile

Pictures: Kloss' Gibbon #1 (31 Kb JPEG) and Kloss' Gibbon #2 (15 Kb JPEG) (Gibbon Res. Lab)

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 population growth.

Tidbits

*** 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. (Macdonald 1984)

Status and Trends

IUCN Status:

1960's: Insufficiently Known
1970's - 1980's: Vulnerable
1994: Endangered
1996 - 2004: Vulnerable (Criteria: A1c+2c, B1+2ac) (IUCN 2004)

Countries Where Kloss' Gibbon Is Currently Found:

2004: Occurs in Indonesia. (IUCN 2004)

Population Estimates:

[Note: Figures given are for wild populations only.]

WORLD (Indonesia (Mentawai Islands))
- 1977: 84,000 ("may be too high") (Nowak & Paradiso 1983)
- 2005: 20,000 - 25,000 (Whittaker 2005)

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

Weight:

Kloss' gibbon weighs about 6 kg (13 lb).

Habitat:

Kloss' gibbon is found in tropical rain forest.

It is one of the species that live in both the Sundaland Biodiversity Hotspot (Cons. Intl.) and the Sumatran-Nicobar Islands Lowland Forests Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Gestation Period:

7 - 8 months.

Birth Rate:

A single young is usually born. There are 2 - 3 years between births.

Diet:

Feeding time usually involves 72% on fruit and 25% on animal matter (Macdonald 1984).

Behavior:

All gibbons are arboreal and diurnal.

Social Organization:

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:

Density:

20 or more individuals/sq km (50 or more individuals/sq mi). (Nowak & Paradiso 1983)

Range:

Territory: About 10 hectares (25 acres). (Nowak & Paradiso 1983)

Home range: 20 - 35 hectares (50 - 85 acres). The territory is about 2/3 of the home range. (Macdonald 1984)

References

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 2005

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Last modified: January 7, 2006;