The nyala (Tragelaphus angasii) is a spiral-horned antelope found only in southern Africa. It is the antelope species with highest sexual dimorphism, which means the male and female look quite different. Only the male has horns, and he is also markedly bigger than the female. An adult male has a deep brown to slate gray coat, with faint vertical stripes on the sides. He has a crest of white hair down the back, as well as yellow legs. The female is reddish-brown, with clear white vertical stripes on the sides. Females do also have a crest of hair down their back, but it is less conspicuous.
Both sexes have the look of females when young, but the male changes coat gradually as he matures. Adult animals with a female coat and male horns have been recorded but are very rare. It is also not known if such individuals are females with horns, or males who never changed coat. A male nyala can reach a height of 110 cm (43 in) up to his shoulders, whereas a female can reach 90 cm (3 ft). Typical weight is 98-125 kg (216-276 lb) for males and 55-68 kg (121-150 lb) for females.
Diet & habitat
Nyalas are mixed feeders and will feed on grass, leaves, twigs, flowers, and fruits. They tend to avoid open areas and will spend most of the day in thick bush. They are commonly seen at water holes as they will drink daily when water is available, although they can survive in drier environments. They are often known to be wary and shy animals, but in areas were the species does well and is numerous, such as Tembe Elephant Park in South Africa, they are quite common to see.
Nyalas live in social groups of 2 to 30 individuals. Mainly females and their young live in large groups. Adult males typically live solitary lives but do form loose groups with both young and adult individuals once in a while. It is common for groups of males to join female groups for short periods. Male nyalas often fight for dominance with their horns, like other species of antelope, but the nyala also has a second strategy to determine dominance between males. Male nyalas will often “tiptoe” next to a rival while showing off his size by erecting his back hair and tail. If done by a dominant male, the lesser rival will often leave without objection. This strategy is also deployed by the closely related bushbuck.
There is no breeding season for nyalas, and they can mate throughout the year. Females normally get a single calf after a gestation period of seven months. Mating often peak in spring and autumn under normal circumstances.
In Tembe Elephant Park, a reserve with high densities of nyala, they are believed to breed a lot more under carnivore pressure. With a growing population of lions and leopards in the park it has caused somewhat of a population boom in nyalas, as they seem to counteract the frequency they are being preyed upon by breeding more. As they are able to breed throughout the year, this has caused the nyala to reach an astounding number in a short amount of time in this reserve.
The nyala is a very common species throughout its range and 80 % of the population is found within protected areas. An estimate from 2013 found there to be around 30,000 nyalas in South Africa alone, with 25,000 of them in the province of KwaZulu-Natal, on the South African east coast. 1,000 animals in Eswatini, 3,000 in Mozambique, 1,500 in Malawi and over 1,000 in Zimbabwe. A small population of 250 exist in Namibia. Nyala numbers are stable or increasing and it is listed as least concern on the IUCN Red List. The males are popular targets for trophy hunters, which has seen an increase in nyalas being introduced to reserves and ranches in South Africa.