Waterbuck

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Waterbuck

Waterbucks belong to the large family of bovids, plant-eating hooved animals with horns and a four-chambered stomach for extracting nutrients from a diet of grass or foliage. These ruminants regurgitate and rechew their food (chewing the cud). Domestic cattle, also members of the bovid family, chew their cuds as well.

Description

waterbucks belong to a subfamily of bovids called the Hippotraginae and are further classified in the tribe Reduncini, which also includes kobs, reed-bucks, and lechwes. Waterbucks are the largest animals in this subfamily, with males weighing more than 500 lb (227 kg) and standing more than 4 ft (1.2 m) at the shoulders. Female waterbucks are slightly smaller. Only male waterbucks have horns, which are V-shaped, tapered, ridged, and curve backward, then slightly forward at the tips.

Two subspecies of waterbuck are recognized: the common waterbuck Kobus ellipsiprymnus ellipsiprymnus and the defassa waterbuck K. e. defassa. Some scientists consider the defassa waterbuck to be a separate species. One distinguishing marking between the two is their coloration. Defassa waterbucks have shaggy, silvery-gray or reddish to dark brown coats with a streak of white on their rumps. Common waterbucks have a distinctive white ring around the rump, the lower half of the legs are black, and they have white markings at the throat, an eyebrow line, and a white snout. Males tend to darken with age.

Waterbucks lack scent glands, but possess a greasy coat with skin glands that secrete a smelly, musk odor that can be detected as far as 1,600 ft (488 m) away. The greasy, shaggy coat serves to protect waterbucks from their damp habitats. Waterbucks do not run rapidly, moving mostly at a trot.

Habitat and population

Waterbucks have even less tolerance to dehydration than cattle. Therefore, they are usually found close to water in regions with ample rainfall.

Waterbucks prefer to eat the protein-rich grasses, herbs, and foliage found in valleys and areas where rain water drains. They are found in the central and south-central African countries of Kenya, Tanzania, Rwanda, Uganda, Zambia, Zimbabwe, and northern parts of South Africa.

In areas where the different subspecies of water-buck overlap, many hybrid individuals have been seen. In a national park in Kenya the population density of waterbucks has been observed to reach as many as 250 animals per sq km while the average is 30 per sq km. These numbers are much higher than their typical density outside the refuge where they average about four animals per sq km. In areas where there is a good water supply, waterbucks tend to live in denser populations.

Social relationships

The importance of proximity to water plays an important role in the social behavior of waterbucks. Not only do they need the water for drinking, but they also use water to fend off predators, for they are good swimmers. Competition to be near water is reflected in male relationships. Male waterbucks are territorial, but they will tolerate several other males within their territory. These so-called satellite bulls are submissive to the dominant male and will help him defend their territory from other males.

Females have loose, come-and-go relationships, congregating in female herds with as many as 30 animals,

KEY TERMS

Coloration —The overall color of an animal, plus distinctive color markings on various parts of the body.

Family —A large group of animals classified together because they share common characteristics of physical structure and consequent behavior.

Herbivore —An animal that only eats plant foods.

Hybrid animals —Animals that are crosses between species or subspecies that have already been classified.

Regurgitation —The casting up of food that has only been partly digested in a stomach chamber of cud-chewing animals.

Satellite bulls —Submissive bulls that the dominant bull tolerates within his territory and that help defend it from other intruders.

including dependent young waterbucks. Female herds may have a home range as large as 1500 ac (608 ha), while bachelor groups have a range of 250 ac (101 ha). Young males form bachelor herds of five to 40 young bulls and there is evidence of a hierarchy among them. These are also loose social groups with members coming and going. Young males join these groups at the age of nine months until they are six years old, their age of maturity.

Female waterbucks conceive after the age of three, reproducing about once a year after an eight-month gestation period. The mother stays with her calf at night, but during the day wanders away from her young. The calf is nursed three times a day for the first two to four weeks and the calf is weaned at six to eight months. Mothers with young offspring tend to remain in woodland areas as a protection from predators.

See also Antelopes and gazelles.