Animal Info - Mountain Nyala

Tragelaphus buxtoni

Status: Endangered


Contents

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 (Size and Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Early Development, Diet, Behavior, Social Organization, Age and Gender Distribution, Density and Range)
5. References


Profile

Picture: Mountain Nyala (34 Kb JPEG) 

Male mountain nyala are a sepia brown color that slowly gets darker with age, while females are of a pale liver color with a scattering of spots and stripes. The mountain nyala weighs up to 300 kg (660 lb) and stands approximately 135 cm (53") at the shoulder. It is found in a mosaic of high-altitude woodland, bush, heath, moorland and valley-bottom grassland, from 3000 m (9800') up to 4200 m (13,800'). 

The mountain nyala eats herbs and shrubs and occasionally grass, lichens, ferns and fallen leaves. Seasonal movement occurs, but it is not extensive. It consists mainly of change in altitude - to lower ground in the rainy season and to higher moorlands in the dry season. Mountain nyala living in forest may emerge into more open areas to feed at night.  During the dry season, between January and March, most mountain nyala live above the forest edge in the heath. Females accompanied by one or two generations of young form frequent but impermanent associations with other mother-young groups. These are regularly joined or monitored by adult males. 

The mountain nyala is endemic to Ethiopia and is limited in its distribution to Ethiopia's Bale and Arussi provinces. Reasons for the mountain nyala's decline include habitat loss and poaching. Natives of the area hunt it for meat and purported medicinal purposes. The lower reaches of its range are more suited to the species than the upper less-vegetated areas, but in most parts of its range, the more suitable habitat has been taken over for cultivation and pastoralism.


Tidbits

*** The mountain nyala was first documented by Western scientists about 1910.

*** It is said that natives of the area where the mountain nyala occurs shoot female nyala in the belief that the urine is a cure for syphilis (Crowe 1967).


Status and Trends

IUCN Status:

Countries Where the Mountain Nyala Is Currently Found:

2004: Occurs in Ethiopia. (IUCN 2004)

Population Estimates:

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

History of Distribution:

The mountain nyala is endemic to Ethiopia and is limited in its distribution to Ethiopia's Bale and Arussi provinces (Murulle Found. 2003).

Distribution Map #1 (7 Kb GIF) (African Mammals Databank 2004)
Distribution Map #2 (5 Kb GIF) (Huffman 2004)

Threats and Reasons for Decline:

Reasons for the mountain nyala's decline include habitat loss and poaching. Natives of the area hunt it for meat and purported medicinal purposes. The lower reaches of its range are more suited to the species than the upper less-vegetated areas, but in most parts of its range, the more suitable habitat has been taken over for cultivation and pastoralism.


Data on Biology and Ecology

Size and Weight:

The mountain nyala stands approximately 135 cm (53") at the shoulder. The female mountain nyala weighs 150 - 200 kg (330 - 440 lb); the male weighs 180 - 300 kg (400 - 660 lb)

Habitat:

The mountain nyala is found in a mosaic of high-altitude woodland, bush, heath, moorland and valley-bottom grassland, from 3000 m (9800') up to 4200 m (13,800'). Stragglers occur as low as 1800 m (6000'). The lower reaches of the mountains, around 3000 m (9800'), in the ecotone between the lower edge of the woodlands and the riverine grasslands, are preferred over the upper, less vegetated areas. The woodlands, heath and bush provide dry-season refuge. During the rainy season there is a greater choice of pasture at lower levels, but only where the habitat has not been converted to other uses. The sedgy grasslands tend to be waterlogged and animals have even been seen eating water plants. 

The mountain nyala is one of the species that live in both the Eastern Afromontane Biodiversity Hotspot (Cons. Intl.) and the Ethiopian Highlands Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Age to Maturity:

Female calves are pregnant by age 2 years (Kingdon 1997).

Gestation Period:

8 - 9 months (Kingdon 1997).

Birth Season:

Mating peaks in December and most births occur in the rainy season.

Birth Rate:

A single young is born (Kingdon 1997).

Early Development:

A young mountain nyala stays closely attached to its mother for as long as 2 years, by which time female calves are themselves pregnant and males join bachelor groups (Kingdon 1997).

Diet:

The mountain nyala eats herbs and shrubs and occasionally grass, lichens, ferns and fallen leaves.

Behavior:

Seasonal movement occurs, but it is not extensive. It consists mainly of change in altitude - to lower ground in the rainy season and to higher moorlands in the dry season. Mountain nyala living in forest may emerge into more open areas to feed at night.  During the dry season, between January and March, most mountain nyala live above the forest edge in the heath. (Brown 1969)

Mountain nyala are more active from 16:00 - 08:00 hours, but they may also be seen feeding between 08:00 and 16:00 hours, especially about 12:00 - 13:00 hours (Brown 1969).

Social Organization:

Females accompanied by one or two generations of young form frequent but impermanent associations with other mother-young groups. These are regularly joined or monitored by adult males. Numbering up to 13, such groupings tend to be smaller in the dry season, when they range very widely. (Kingdon 1997)

Average herd size: 5.7 (range: 2 - 13, most: 2 - 6). It appears that even when the mountain nyala was much more common, the average herd size was not much larger. In fact the herd sizes have apparently not changed appreciably in 60 years, despite a reduction in both the range and numbers of the species. (Brown 1969)

Age and Gender Distribution:

In one study (Brown 1969), of 252 animals considered to be accurately sexed, 37 (14.7%) were males, 170 (67.8%) were females, and 44 (17.3% ) were calves. The indicated percentage of males was considered probably to be on the low side, since older males in particular are more secretive and harder to locate.

Density and Range:

Densities: 

  • Bale National Park: can be more than 20 individuals/sq km (50 individuals/sq mi) (Kingdon 1997)
  • Arussi: 1.5 - 2.5 individuals/sq km (3.9 - 6.5 individuals/sq mi) (Brown 1969)
  • Bale: 3 - 7 individuals/sq km (7.8 - 18.2 individuals/sq mi) (Brown 1969)

Female mountain nyalas restrict their movements to about 5 sq km (2 sq mi) during the rainy season. Males occupy a range of up to 20 sq km (8 sq mi). (Kingdon 1997).


References

African Mammals Databank 2004, Blower 1968, Brown 1969, Burton & Pearson 1987, Crowe 1967, Curry-Lindahl 1972, Hillman 1986, Huffman 2004, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Kingdon 1997, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Schuhmacher 1967, Stuart & Adams 1990, Stuart & Stuart 1996


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Last modified: November 4, 2005;

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