Waterbuck

Kobus ellipsiprymnus

General Description

Scientific Name: Kobus ellipsiprymnus

Subspecies:

Common Waterbuck (K. e. ellipsiprymnus)
Defassa Waterbuck (K. e. defassa)

Status: Least Concern (decreasing)

Population Estimate: 200,000

Population in Assessed Areas: 158

Diet: Herbivore - grazer

Male Size: 200-270 Kgs

Female Size: 150-200 Kgs

Trophy Size: 71.12 cm minimum

Generation Length: 7.1 years

Reproductive Season: Year Round

Time of Activity: Diurnal

Description: Males are typically larger and weigh more than females. Males are usually around 220 – 270 kg and 130 – 150 cm tall (shoulder height), while females are generally about 150 – 200 kg and 100 – 125 cm tall (shoulder height). Only males bear horns, but small horn growths are sometimes found in females. Adult horns are v-shaped, curved forwards, and prominently grooved across 60 - 70% of their length. Horns reach between 60 and 80 cm when fully grown, and Rowland Ward’s minimal trophy size is usually reached at 7 years old.

Waterbuck is known for its smelly gland secretions. The two subspecies, common waterbuck and Defassa waterbuck, have similar greyish-brown hair between 4 and 7 cm long and white markings on the rump, eyebrows, muzzle, and throat. Defassa waterbuck rump markings tend to be a solid patch, while common waterbuck rump markings are a white ring 4 cm thick. Defassa waterbuck pelage varies across geographical locations between a reddish brown, pale grey, dark grey, blackish-brown with red speckles, and sand-brown.

Ecology: The preferred habitat for waterbuck includes savannah plains with woodlands or bushy clumps and permanent drinking water at least 1.8 km away. This means waterbuck are usually found in floodplain, riverine, or marshy areas with bushveld thickets and scattered trees for shade. Waterbuck are also frequently seen around mountain foothills. Defassa waterbuck are usually limited to areas with at least 750 mm of rainfall annually, while common waterbuck can inhabit drier regions. Waterbuck has been found as high as 2,100 m in Ethiopia. Waterbuck do not find overgrazed habitats suitable, and there is evidence of waterbuck leaving areas due to competition with nyala.

Waterbuck are ruminants whose diet consists of 70 - 92% soft and roughage medium to tall grasses, 2 - 5% browse, and smaller amounts of forbs, fruit, and herbs. Waterbuck prefers sweet grasses, but also grazes on reeds and water grasses. Common grasses eaten by waterbuck include Guinea grass (Panicum maximum), Pangola-grass (Digitaria eriantha), red grass (Themeda triandra), spear grass (Heteropogon contortis), and Andropogon amplectens. During the dry winter and/or if competition is high, waterbuck will eat greater quantities of roughage material. When fodder runs out, waterbuck leave in search of a more suitable habitat. Waterbuck drink at least twice a day, taking in around nine litres daily.

Behavior: Waterbuck are semi-gregarious and usually found in groups of 4 to 30 individuals depending on population density and season. Group size tends to decrease in the dry winter when food becomes scarce. The waterbuck social structure includes:

Families of adult cows and calves, potentially with a dominant bull
Groups of bachelor males
Groups of heifers between 1 and 3 years old
Solitary, territorial bulls between 6 and 10 years old
Solitary post-mature bulls older than 9 years

Waterbuck generally lack family bonding, meaning individuals move between groups often. Most calves are chased away once they finish weaning, cows by their mothers, and males by the dominant bull. When cows reach social maturity at 2.5 - 3 years, they leave their current group to join another or start their own. Bachelor male groups have social hierarchies based on strength and size. Males leave their bachelor group to challenge other bulls for territory when they reach social maturity at around 5 - 6 years of age. These territories are between 40 and 150 ha and are occupied by the same bull for as long as 4 years so long as they are not replaced by a more dominant bull. Displaced bulls over the age of 9 - 10 become solitary nomads. Territories are defended with aggression, where bulls display dominance by stretching their head up high, tipping their horns forward, or ploughing up and throwing grass. Conflict between competing territorial males is often fatal. However, when food supply is scarce, dominant bulls may lose their territorial behaviours and join a family group instead. Family group ranges last as long as 8 years and are between 150 and 780 ha, often overlapping with 5 - 8 male territories.

Common predators include leopards (Panthera pardus), lions (Panthera leo), African wild dogs (Lycaon pictus), hyenas (Crocuta crocuta), and Nile crocodiles (Crocodylus niloticus).

Reproduction: Mating occurs year-round. Bulls reach sexual maturity at 14 months and social maturity at 5 - 6 years. Dominant bulls will mate with 3 - 4 cows in oestrus who pass through their territory. Cows reach sexual maturity at 13 months and social maturity at 2.5 years. Cows start calving at 3.3 years old.

Cows have a gestation period of 8.5 months and a calving interval of 14 - 16 months. After giving birth, calves will hide themselves without their mother’s help in riverine thickets, where their mother will suckle them frequently for the first three weeks. Mothers consume their calves’ after birth and commonly give birth to twins or triplets. Calf mortality due to predation is very high until weaning at around 7 months old.

Conservation Analysis

Map of Waterbuck Distribution

Current & Historic range: Waterbuck currently occupy Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, The Democratic Republic of the Congo, Côte d'Ivoire, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Malawi, Mali, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Somalia, South Africa, South Sudan, Sudan, Swaziland, Tanzania, Togo, Uganda, Zambia, and Zimbabwe (IUCN, 2016).

Defassa waterbuck is found west of the western Rift Valley and is distributed from as high as southern Mali to as low as Angola, while common waterbuck is found east of the eastern Rift Valley (Spinage, 2013).

Waterbuck are extinct in Gambia, although vagrants may cross over from Senegal (Spinage, 2013). While common waterbuck is extinct in Ethiopia, Defassa waterbuck is not. (Spinage, 2013).

Current & Historic Populations: The most recent total population estimate for waterbuck is 200,000, including around 105,000 common waterbuck and 95,000 Defassa waterbuck (East, 1999). No global population estimate is available. More than half of the total waterbuck population is on protected and private land (East, 1999). Significant common waterbuck populations include (East, 1999):

In Kenya: Tsavo, Laikipia, Kajiado, Lake Nakuru, coastal rangelands
In Tanzania: Tarangire, Selous-Mikumi
In Zambia: Luangwa Valley
In South Africa: Kruger, Hluhluwe-Umfolozi, private land.

This population trend is said to be decreasing by the IUCN (2016), but the waterbuck is of Least Concern. The waterbuck’s historical range was throughout most of sub-Saharan Africa but has since been widely reduced. Historical total population estimates are unavailable.

Threats to Species Survival: While waterbuck widely occupy protected areas, some populations of Defassa waterbuck, in particular, have undergone large declines due to poaching, including populations in the National Parks, Queen Elizabeth, Murchison Falls, Akagera, Lake Nakuru, and Comoe (Spinage, 2013).

Recommended Conservation Actions:

Further resource and manage protected areas where waterbuck populations exist.
Implement harvest management strategies such as catch limits and controls on waterbuck hunting.
Improve survey methods to get accurate population data, such as implementing long-term monitoring programs.

Economic & Cultural Analysis

Ecotourism Value: Moderate-High

Hunting Value: High

Meat Value: High

Average Trophy Value: $2,000-2,500 USD

Meat Yield per Animal: 30-60 kg

Economic Value/Impacts: Waterbuck are often a valuable species to ecotourism operations across their range, but often less so than larger species, or others that are more recognizable such as wildebeest, zebra or buffalo. Few tourists will visit a place just to see waterbuck, as they are outshone by more charismatic megafauna.

They have also become increasingly valuable to international hunters, both in their native range, and in parts of their introduced range in the eastern cape of South Africa. Their lyre shaped horns and large body size makes this species a desirable trophy, with purposeful stocking of this species being common on high fenced properties, even outside their historic range, such as many of the populations in the eastern cape of South Africa. Artificial water sources allows many landowners to stock waterbuck in areas where they may not have existed.

Cultural Value: Waterbuck have likely been hunted by humans and our ancestors for millions of years, and due to moderate size, historical abundance, and palatable taste, would have likely been a staple to many communities. They are often depicted in traditional art and folklore, and their meat is considered a delicacy in some regions, though in others it's disliked, often due to the "rutty" smell of older males during the mating season.

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