Defassa waterbuck (Kobus ellipsiprymnus)
Defassa waterbuck (Kobus ellipsiprymnus) have long bodies and necks and short legs, coarse hair and they have a mane on their necks. Their head and body length ranges from 177 – 235 cm and shoulder height from 120 – 136 cm. Only male waterbuck have horns, which are curved forward and vary in length from 55 – 99 cm. The length of their horns is determined by the age of the waterbuck. Body color ranges from gray to red-brown and darkens with age. The lower part of the legs is black with white rings above the hooves.
This large antelope is considered, by some authorities, to be a distinct species, K. defassa (the common waterbuck found east of the Rift Valley with a white on its rump), but the two races interbreed where they overlap.
Defassa waterbuck live in small herds and are most often seen grazing near water. They are found in suitable habitats in all four of Uganda’s savanna national parks: Murchison Falls, Queen Elizabeth and Kidepo Valley National Parks.
Waterbuck prefer grassland habitat that is close to water. The best habitats are by draining lines and in valleys. While they prefer dry ground, they remain close to water for food and as an escape from predators.
Waterbuck live in wide, separated ranges that are shared by many females and territorial and non-territorial males. The size of a waterbuck’s home range depends on the quality of the habitat, population, and the age and fitness of the waterbuck. When they’re in good health and are younger have the largest ranges.
The home ranges of females may overlap, resulting in small herds that average 5 – 10 animals. Within these herds, there is no established rank order. Females, however, are most commonly found alone or in pairs, and it is believed that herds of waterbuck are random meetings of individual waterbucks.
Horns begin to form on males at 8 – 9 months, which marks their separation from the females. These young males then form bachelor herds and remain in these until they mature. The bachelor herds are composed of anywhere from 5 – 10 waterbuck. These are closed groups and the hierarchy is based on seniority.
Upon maturation, the bulls become territorial. The activity of the waterbuck is affected by seasonal differences, habitat, grazing conditions, distance from water, and the number of predators in the area. When there is less water available and the conditions are dry, waterbuck need to rest more. While they have been found active at night, the waterbuck is more likely to be active in the daytime.