Common Tsessebe, Damaliscus lunatus
The common tsessebe (Damaliscus lunatus), also known as the sassaby, is most closely related to the bontebok and the topi, which share its genus. The common tsessebe is classified within the subfamily Alcelaphinae, which holds five species, and these are placed within the Bovidae family. It is most commonly found in South Africa, Botswana, Namibia, Zambia, and Zimbabwe, although it once had a larger range across Africa. It prefers a habitat within open plains, grasslands, and slightly wooded areas, but in can be found rolling uplands or flat plains occasionally.
The common tsessebe can reach an average height of 4.8 to 7.5 feet, and a weight of 302 pounds in males. The horns of the males can grow to be 1.3 feet, while female’s horns reach an average length of 1.2 feet. The fur of this species is typically burnished brown, with black faces and tail tufts. The underbelly is typically white, while the forelimbs are grey black or blue back and the hind limbs are yellow or yellow- brown in color.
The common tsessebe is a social species, with females composing groups of up to ten including young and young males forming bachelor groups of up to thirty. Older males will form territorial groups of up to thirty, in the form of a lek, which is used for mating purposes. Territories are claimed with many behaviors, including high stepping, mud packing, defecating, and grunting, but the most used form of claiming territory occurs when the tsessebe rubs its horns on the ground. One behavior may be used for scent marking, which includes the male tsessebe places grass stems into the preorbital glands located near the eyes, and then rubbing its horns and forehead with the scented grass. This behavior has not often been observed.
Some behaviors of the common tsessebe have confused scientists because they show no real purpose. Many sleeping individuals have been observed placing their mouths on the ground while keeping their horns pointed straight up. Males of this species have been observed standing in parallel lines with their eyes closed, nodding their heads in a back and forth motion.
The breeding season for the common tsessebe occurs between the months with the onset of older males forming leks. These lekking groups are formed in an area where females gather specifically for mating. It has been observed that females choose which male they will mate with, regardless of a male’s possible influence. Dominant males will gather in a closer group within the lek, having a higher chance of breeding, but there are other factors for females to choose a mate including protection from predators and resource availability.
One study showed that leks are shaped when males compete for dominance, between February and March. The strongest males reach the center of the lek, and may hold that territory for a long period. Although the males in this area are more likely to breed, they must also protect the group from predators, and therefore run a great risk. Once breeding has occurred, a female may be pregnant for up to seven months, after which she will give birth to one bay tsessebe. Sexual maturity is reached at two or three years of age.
The diet if the common tsessebe consists of grasses found in its range, which it will consume in the morning hour between eight and nine, as well as four in the afternoon. The other hours of its day are spent resting, digesting food, or watering in the dry season. This species can fall prey to leopards and lions, especially if individuals are trying to avoid territories of older male tsessebes.
The common tsessebe is threatened by habitat destruction and over hunting in some areas of its range. In 1998, the populations of this species were estimated to be viable, although low, and so it was not listed as endangered. Despite this, it was found to have been on the decline, and was estimated to become extinct by 2025 if no conservation efforts are conducted. The common tsessebe appears on the IUCN Red List with a conservation status of “Least Concern.”
Image Caption: Tsessebe, Okavango, Botswana. Credit: Paulmaz/Wikipedia (CC BY-SA 3.0)