Tragelaphus angasiinyala

Geographic Range

Nyala have a localized distribution, occupying some parts of southeastern Africa.

Habitat

Nyala are found near thickets in dry savanna woodland, and prefer proximity to high quality grassland and fresh water as well.

Physical Description

Nyala are medium sized in comparison to other antelopes, with a marked size difference between the sexes. Males weigh 98-125 kg and stand over one meter tall at the shoulder, while females weigh 55-68 kg and are slightly less than a meter tall. Males have horns, which can be up to 80 cm long and spiral upwards, curving out at the first turn. Females and juveniles are usually a rusty red color, but adult males become slate gray. Both males and females have a dorsal crest of long hair that runs from the back of the head to the base of the tail, and males additionally have a fringe of long hair along the midline of their chest and belly. Nyala have some white vertical stripes and spots, the pattern of which varies.

  • Range mass
    55 to 126 kg
    121.15 to 277.53 lb

Reproduction

Nyala can breed at any time of the year, but there is a breeding peak in the spring and a smaller peak in the autumn. A female's estus cycle is about 19 days long. Males court females for two days of this cycle, but females are receptive to mating for only 6 hours per cycle. Gestation takes 7 months, after which a single, 5 kg calf is born. The young are born out of the sight of potential predators (lions, hyenas, leopards, wild dogs) in a thicket. A calf remains hidden for up to 18 days, during which time the mother returns periodically to clean and nurse it. Offspring remain with their mothers until her next calf is born, but after that courting males drive adolescent males away from their mothers.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    7.33 to 8.4 months
  • Average weaning age
    7 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    452 days
    AnAge
  • Parental Investment
  • altricial
  • post-independence association with parents

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    18.5 years
    AnAge

Behavior

Nyala are gregarious, generally staying in groups of two to 30 individuals. Females sometimes remain near their mothers after they have offspring themselves, so relatedness within female groups may be relatively high. Males also form groups, but these associations are much more transitory, with no long term association between particular males. The species is not territorial, and home ranges often overlap. Larger numbers of individuals may come together at a good feeding site or a water source. Adult males fight when in the presence of a female in estrus. A male displays to another male by raising his dorsal crest of white hair, holding his head high, and raising his tail. If aggression occurs it may be violent; males have been known to be killed by a thrust of their adversary's horns. Generally it is the larger of two males that is the victor and subsequently mates with the female. This species has a variety of stereotyped behaviors associated with dominance interactions and courtship.

Nyala may be active during the day, but it is more common that their activities are concentrated in the evening and night. They spend much of the day concealed in brush, particularly the hottest part of the day. They are vulnerable to several predators, and members of female groups give an alarm call, a deep barking vocalization that results in the flight of other nyala within hearing range. They also react to the alarm calls of several other species - impala, baboons, and kudu. Impala react to the alarm call of the nyala as well. Nyala sometimes follow feeding baboons, taking advantage of the fruits and leaves that the baboons dislodge from trees.

Communication and Perception

Food Habits

These antelope both graze and browse. They eat the leaves, twigs, flowers and fruits of many different species of plants. During the rainy season they mainly eat the fresh green grass. They drink daily when water is available, but they can survive in areas where water is only available seasonally.

Economic Importance for Humans: Positive

These antelopes have probably historically been hunted as food animals.

  • Positive Impacts
  • food

Conservation Status

Nyala currently have a more limited distribution than they have had in the past. Recently in some areas their habitat has actually been improved through human activities, such as shifting agricultural techniques resulting in abandonment of fields and subsequent bush encroachment, and overgrazing of grasslands by cattle, which results in invasion by many herbs that nyala eat.

Contributors

Deborah Ciszek (author), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

food

A substance that provides both nutrients and energy to a living thing.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Estes, R.D. 1993. The Safari Companion. Chelsea Green Publishing Co., Post Mills, Vermont.

Skinner, J.D. and R.H.N. Smithers. 1990. The Mammals of the Southern African Subregion. University of Pretoria, South Africa.