The southern reedbuck is larger than the other species in Redunca, namely Bohor Reedbuck or Mountain Reedbuck.
It stands 80–90 cm (31–35 in) at the shoulder. Females weigh 48 kg (106 lb), while the males weigh 68 kg (150 lb).It has distinctive dark lines running down the front of each of its forelegs and lower hind legs and whitish rings around the eyes. It has a lifespan of 10 years.
The coat is silky and almost woolly. The color of its coat ranges between light- and greyish-brown, and may be lighter on the neck and chest. A small, black, bare glandular patch can be noticed at the base of each ear. White fur covers the underparts and the areas near the lips and chin. The tail is white underside, and appears short and bushy. Southern reedbucks measure an average of 85 cm (33 in) at the shoulder. Females lack horns. Males bear forward-curving horns, about 35–45 cm (14–18 in) long, with the base having a distinct band of pale, rubbery tissue.
Southern reedbucks live in pairs or alone. Sometimes, they form herds consisting of about 20 members. They prefer to lie in grass or reed beds in the heat of the day and feed during sunrise and sunset , or sometimes even at night. Old reedbucks are permanently territorial, with territories around 35-60 hectares, and generally live with a single female, preventing contact with rival males. Females and young males perform an 'appeasement dance' for older males. During the dance, the bucks run around speedily and take considerably long jumps, with the tail curled up and scented air being released from a pocket in the groin at every bounce, making a popping sound. Within this territory, it is active all the time in summer, but it is nocturnal in the wet season. It regularly uses paths to reach good sites to rest, graze, and drink water. Average lifetime home ranges have been estimated as 123 ha for females and 74 ha for males.
Their main predators include lion, leopard, cheetahs, spotted hyenas, Cape hunting dogs, pythons, and crocodiles. They can camouflage themselves in the grasslands due to their coats which are almost the same color. If startled or attacked, they stand still, then either hide or flee with an odd rocking-horse movement, and cautiously look back to ensure the danger is gone, generally. They use vocalizations like a shrill whistle through their nostrils and a clicking noise to alert others about danger.
As a herbivore, the reedbuck mainly feeds on grasses. It also eats herbs and reeds. It never enters into water, though it inhabits places with water sources. It needs to drink water every few days to several times a day during the dry season.
The southern Reedbuck breeds almost all the time of the year, although most matings occur during the hot and wet season. Females reach sexual maturity when they are two years old, when they leave their parent’s territory. Males, which reach maturity at a slightly older age, may remain with the family group until their third year. A single young is born per birth after a gestation period of seven to eight months, and remains amongst the dense and tall grass cover in which it was born for the next two months. The female does not stay with her young, but instead visits it for just 10 to 30 minutes each day to nurse it.
Southern Reedbucks have a wide distribution, stretching from Gabon and Tanzania to South Africa.