The African Elephant’s 
Drinking Problem 
On the way to the river that is their main source of water, elephants raid crops. 
Local farmers complain, but ivory hunters are making a killing 
by Janies Allaway 
On its meandering journey through 
the bushland of eastern Kenya, the 
Tana River — Kenya’s longest — has 
carved a shallow trough in the semi- 
arid plains. The river is virtually the 
only permanent surface water in this 
periodically desiccated region, and 
vegetation grows more richly here. 
What happens on the river’s narrow 
flood plain is crucial to the region’s 
human population and herds of ele- 
phants. 
Of all Africa’s wildlife, elephants 
have perhaps the greatest ecological 
impact and most marked interactions 
with people. Elephants can greatly af- 
fect the structure and species com- 
position of vegetation, thereby influ- 
encing the habitats of other wild ani- 
mals, domestic livestock, and people. 
They can be significant conduits of 
nutrient and energy flows. Elephants 
are also a major tourist attraction, of- 
ten damage farm crops, and their ivory 
has for centuries been one of the most 
highly valued and violently contested 
products of the continent. 
Harsh and mostly undeveloped, the 
lower Tana region has long been a 
stronghold of elephants. In recent 
years it has increasingly come to be 
a focus for agricultural, ranching, wa- 
ter-resources, and tourism develop- 
ment. Through a study of how ele- 
phants use the area and interact with 
people, carried out in cooperation with 
the then Game Department of Kenya, 
I hoped to provide part of the eco- 
logical understanding needed to guide 
the dramatic changes in land use com- 
ing to the region. The key elements 
were the elephants’ seasonal patterns 
of movement and habitat use and their 
two principal conflicts with people: 
elephants' raiding of farms along the 
river and the widespread illegal hunt- 
ing of elephants. 
For much of the 300 miles of the 
Tana’s lower course, its flood plain 
varies from a few hundred feet to a 
couple of miles in width; below the 
village of Wenje, 57 miles from the 
coast, it gradually widens into a broad 
delta extending to the Indian Ocean. 
Central in the flood plain’s importance 
to elephants is the flux of the equa- 
torial seasons, marked by the sun’s 
semiannual north-south passage. 
Shifts in the prevailing monsoon winds 
bring two rainy seasons to the lower 
Tana, interspersed with extended dry 
periods. The river, fed by rainfall on 
the Aberdare Mountains, Mount 
Kenya, and other uplands of central 
Kenya, usually floods twice a year. 
The floods are unpredictable in their 
magnitude and timing, however, and 
storms within the region are often lo- 
calized. Thus the elephants, other 
wildlife, and people must cope with 
an environment alternately wet and 
dry — and often unpredictably so. 
Elephants cope by moving over vast 
areas of the interior — perhaps 15,000 
square miles on the west side of the 
river — when water is available there 
and falling back on the permanent 
supply of the Tana River as the in- 
terior dries up. This kind of seasonal 
movement, called a dispersal/concen- 
tration pattern, is typical of many wa- 
ter-dependent mammals, including 
traditional pastoralists and hunters. 
During a rainy season and for sev- 
eral weeks afterward, elephants roam 
over large areas, drinking from the 
countless shallow depressions and 
larger rain pans. New grass shoots, 
herbs, and bushes and trees lush with 
new leaves provide abundant food. 
Then, as sun, wind, and drinking by 
elephants, cattle, and other animals 
drain the rain pans, the elephants be- 
gin to pull back toward the Tana and 
its flood plain. 
Most basically, the river provides 
elephants with drinking water. In dry 
months, however, the river is not ac- 
cessible along all its banks. Banks are 
commonly six to ten feet high, and 
only slope gently enough for elephants 
to clamber up and down at scattered 
sites, mostly at the inside of a meander 
curve or the mouth of an oxbow. This 
restriction on elephant drinking influ- 
ences which areas they travel through, 
feed in, and encounter people. 
During dry times the flood plain 
and nearby areas must also supply 
the prodigious quantities of plant ma- 
terials elephants eat. Flood-plain vege- 
tation is an intricate mosaic, shaped 
by past changes in the river’s course, 
underlying soil conditions, and cutting 
and burning by people of the Pokomo, 
the Orma, and related tribes. Patches 
of forest often occur on higher sites, 
dense spiny thickets and herbaceous 
plants in low backwater areas, grass- 
lands on middle elevation flats, and 
banana plantations or fields of other 
crops near the river. The complexity 
is increased by the various stages of 
regenerating forest and bushland 
growing on abandoned farm fields and 
former river channels. Thus the flood 
plain provides a variety of habitats 
to feed in, and the elephants use all 
of them. 
Elephants do not limit their feeding 
to the flood plain, however, even when 
the only drinking water is there. My 
Bob Caputo 
30 
