Waterbuck (Kobus ellipsiprymnus)
Size: 
Head and body length:
177 – 235 cm
Tail length: 33
– 40 cm
Shoulder height:
120 – 136 cm
Weight: Male 200 – 300 kg; Female 160 – 200 kg
Description:
The waterbuck is one of the
heaviest antelopes. Long body and neck,
short stocky legs, shaggy neck mane.
Coloration gray to red-brown, darker with age. Lower legs black with white ring above
hooves, white rump patch, underparts, throat patch, ear-linings, eyebrows, and
snout. They exude a strong turpentine scent. Females do not have horns.
Breeding:
Females rarely conceive
before 3 years of age. Breeding can take
place any time of year, so males guard their territories year-round. Gestation is 8 – 8 ½ months. About two days before giving birth, females go
into dense thickets, where they will give birth to a single calf. Calves can stand in about ½ hour, can outrun
a person within 24 hours, and will generally bolt rather than freeze when
startled. Young are often found
wandering alone or in groups, but the adult herd is almost always nearby for
them to run to if scared or threatened.
Where to look for them:
As their name would suggest,
waterbucks maintain a close association with water, and will almost always be
within one kilometer of it. They often
retreat to water when threatened, and will sometimes submerge until only their
heads are above water. Look for them in
low ravines, near watering holes, and along the delta. They move very little during the day, so if
you see one early in a game drive, check that spot again on your return.
What to notice:
- Young males generally leave the home range when
their horns start to appear (8-9 months), at which point they congregate
in bachelor herds. Watch these
herds for sparring as they try to establish dominance. Only the strongest will have the
opportunity to establish their own territory, and few are strong enough to
do so before they are six or seven years old.
- One unusual trait is that a dominant male will
often allow up to three additional adult “satellite males” to remain with
his herd, as long as they regularly perform an appeasement ceremony. To determine which is the dominant male,
look for the largest and darkest one with the biggest horns, and look for
submissive behavior from the non-dominant males.
Conservation Status:
Not endangered. Although they are less plentiful than some
other antelopes, this is because their habitat requirements are very specific.
Lifespan: Up to 18 years
Detailed Information:
Order: Artiodactyla
Suborder:
Ruminantia
Family:
Bovidae
Tribe:
Reduncini
Genus:
Kobus
Species:
ellipsiprymnus
Sub-species: defassa
Habitat:
Limited to
grasslands within 1 km of water. It is
the most water-dependent of the antelopes, very subject to dehydration in hot
weather. Because of the need for water
and for cover as well as grasslands, their distribution is patchy, following
drainage lines and valleys (remember
where we saw them in Murcheson – right in the river beds). (Estes, p. 107)
Range/Parks:
The defassa subspecies lives west of the
Rift Valley across to the farthest extent of West Africa.
Home Range:
Depends on
quality of habitat, population density, and age of individuals. Range decreases with an increase in age or
density. Home range can vary from 100 –
600 hectares or more, territories from 4 – 146 hectares. (Estes, p. 108)
Waterbucks rarely
move more than about 1 km per day. (Estes, p. 109)
Food/Water:
Feeds on a wide
variety of grasses, but needs a high protein intake due to high water intake
and urine output. When green grass is not
available, it supplements with other herbs and browses acacias and other
shrubs. (Estes, p. 107)
Very
water-dependent, hence the name.
Breeding:
Females rarely
conceive before 3 years of age. Breeding
can take place any time of year, with about 10 months between generations. Gestation is 8 – 8 ½ months. Perennial breeding means males defend their
territories all year long. (Estes, p. 110)
Two days or so
before giving birth, females isolate themselves in dense thickets, where they
will give birth to a single fawn, usually early in the morning. Calves can stand in about ½ hour, and can
outrun a person within 24 hours and generally bolt rather than freeze when
startled. (Estes, p. 110)
Weaned at 6-8
months. Young are often found wandering
alone or in groups, but the adult herd is almost always nearby for them to run
to if scared or threatened. (Estes, p. 111)
Young stay
concealed for 2 weeks. (Kingdon, p. 408)
Social
Organization:
Territorial, but
not fiercely so. Bachelor males are
often tolerated in territory and are even allowed near harem females. (Estes,
p. 107)
Female herds of
5-10 are often seen, although the individuals are shifting and there is no
clear leader. Females are most often
seen singly or in pairs. There may be
some persistence in bonds between mothers and daughters. (Estes, p. 108)
Male offspring
are forced out of the herd at 8-9 months, when their horns start to
appear. They then join bachelor herds
until they reach maturity. These herds
may be as large as 60, but are amorphous, as with the female herds. There is a hierarchy based on seniority in
these groups, and there are frequent challenges and sparring matches. (Estes,
p. 108)
Males are at
their peak from 7-9 years. They will not
attempt to compete for a territory until they are at least 6, even though they
reach sexual maturity at 3 years. This
may be because the territories are so large that there is fierce competition
and they must be very strong to gain and hold a territory. Average tenure is 1 ½ - 2 years. (Estes, p.
108)
It can be
difficult to recognize the territorial male due to the presence of satellite
bachelors, but generally the darkest male with the largest horns will be
dominant. (Estes, p. 109)
Communication:
To assert its dominance, a territorial male
will approach a subordinate male or stand in erect posture with neck arched and
tail held out. May also angle and shake
horns. Subordinate will extend his neck,
open mouth and make chewing motions. (Estes, p. 109)
To get her calf to follow, a mother will
raise her tail as a signal – this is not found in other antelopes. (Estes, p.
111)
Activity
Patterns:
Disperses in the
wet season, when females with calves frequent woodlands; dry season they are in
open grassland near water. (Estes, p. 107)
Variable
depending on latitude and habitat.
Typical grazer activity peaks at the beginning and end of the day, and
spends the rest of the time ruminating and dozing (ruminants rarely actually sleep).
In Queen Elizabeth National Park,
females during the dry season were observed feeding all day long. (Estes, p.
109)
Sign:
Feces are quite
large, and are often found in solid masses rather than as individual pellets. (Walker, p. 188)
Predators:
Lions, leopards, hyenas, crocodiles. Large males will sometimes confront lions
rather than flee. (Estes, p. 111)
References:
Estes, R. (1991).
The Behavior Guide to African Mammals. Berkeley, CA: The University of California
Press.
Kingdon, J.
(1997).
The Kingdon Field Guide to
African Mammals. Princeton,
NJ:
Princeton
University Press.
Walker, C.
(1996).
Signs of the Wild: A Field Guide
to the Spoor & Signs of the Mammals of Southern Africa.
(5
th Edition).
Cape
Town, South Africa:
Struik Publishers Ltd.
Photo by Mark Jordahl