Paul Ehrlich (Bing Professor of Population Studies and
Professor of Biological Sciences, Stanford University) and
Anne Ehrlich (Senior Research Associate, Department of
Biological Sciences, Stanford) are familiar names to
ecologists and environmentalists everywhere. But while most
folks are aware of the Ehrliehs' popular writing in the
areas of ecology and overpopulation (most of us, for
instance, have read Paul's book The Population Bomb), few
people have any idea of how deeply the Ehrlichs are
involved in ecological research (the type that tends to be
published only in technical journals and college texts).
That's why we're pleased to present this regular
semi-technical column by these well-known
In the last three columns, we've seen how resources are
partitioned among the wild herbivores of the Serengeti
ecosystem. Kenyan wildlife biologist David Hopcraft, along
with his wife, Carole, has used such knowledge to launch a
successful "game ranch."
Though cattle are viewed as a source of wealth by many
African peoples, such as the Masai, the animals
are—from an ecological point of
view—actually a source of poverty in hot, semiarid
climates. Cattle (and goats and sheep) must walk daily to a
water supply to drink. This passage consumes a good deal of
energy and slows the rate at which the animals gain weight.
It also results in the trampling of valuable grasses and
compacting of the soil surface.
On the other hand, wild herbivores have much less need to
drink. Some, such as eland, oryx, and Grant's gazelles, may
even obtain all the water they require from the vegetation
they eat. Others drink some water but still need much less
than do cattle. This is because most native African
herbivores conserve water much more efficiently in
digestion. For example, nearly all of the moisture is
extracted from the intestinal contents of gazelles, and dry
feces are released.
Cowpats, in contrast, are produced moist, and rapidly lose
ammonia (and thus the vital nutrient nitrogen) to the
atmosphere. They then dry in the sun and heat up, killing
the bacteria and fungi that might speed their
decomposition. The flat, dried cowpat even kills the grass
The dry fecal pellets of antelope, however, are roughly
spherical. They fall between the grass blades, do not heat
up, and retain their nitrogen. Rather than tending to
create a "fecal pavement," as cattle droppings do, they
break down readily and return nutrients to the soil.
Moreover, like most grazers, cattle have quite specific
food preferences—they graze some grass species heavily and
others not at all. In cattle-raising areas, the species
composition of the forage changes, with those grass species
not eaten by cattle becoming increasingly common. But, as
we described in our first column on the Serengeti ecosystem
(MOTHER EARTH NEWS N0. 91), the native herbivores partition the
available plant species, their diets complementing each
other to one degree or another.
Thus, not only are the water-conserving native herbivores
better adapted to the semiarid habitat of the African
savanna, but they don't degrade it physically or
chemically. Cattle, however, parading back and forth to
water holes and producing their destructive droppings, have
been a major engine of desertification on the continent.
All of these differences led David Hopcraft to conclude
that the soundest way to exploit African grasslands is not
to graze cattle on them, but to organize ranches to raise
and harvest native herbivores. On their 20,000-acre ranch
on the Athi Kapiti plains near Nairobi, the Hopcrafts have
been putting that theory into practice since 1978.
Ecological Costs of Exotic Livestock Grazing
The ranch is stocked with a variety of grazers and
browsers, including antelope, zebras, giraffes, and
ostriches. Cattle are being phased out and may one day be
replaced by African buffalo. For the present, however, the
cattle serve as a valuable "control" for comparing costs
and meat yields with those of the native animals.
A great deal of research is being carried out at the ranch.
The dynamics of the various populations are carefully
tracked, and the food preferences of the different animals
are recorded. When we visited the Hopcrafts in early 1984,
two veterinarians were at the ranch studying the parasites
of harvested animals.
So far, the results of the experiment are exceeding the
Hopcrafts' early hopes and expectations. The herds of
native herbivores—and the meat yields from
them—have been steadily increasing. Simultaneously,
the condition of the range has been improving—even
though the combined weight (biomass) of cattle and native
herbivores has increased by some 35% in the past few
Harvesting is efficient and more humane than in a typical
slaughterhouse. One night each week, men in Land-Rovers
spotlight surplus male animals and dispatch each one
instantly with a high-velocity bullet to the brain. The
other animals are not distressed. Then each carcass is
rapidly processed under the scrutiny of the government
The Hopcrafts are also experimenting with various ways of
marketing the meat, which they describe collectively as
"African venison." Having eaten steaks from many African
herbivores, we can testify that when the animals are
properly slaughtered and the meat carefully prepared, such
food is delicious. We tried several new dried "jerky"
products at the ranch and quickly became addicted to them.
The venison is also being smoked and converted into
sausages and salamis.
Multiple Advantages of African Game Ranching
It seems to us that the Hopcrafts have established the
basic economic feasibility of African game ranching. Costs
are substantially lower than those of cattle raising in
that region. Much less water has to be supplied to the
animals, meaning less capital must be sunk into bores,
dams, and piping. And, unlike cattle, game animals require
no dipping or inoculation against parasites and
Moreover, there is no need for herding or
corralling—the native herbivores handle their own
predator protection. Indeed, the Hopcrafts' herds have been
expanding in spite of almost no predator control. Lions,
cheetahs, hyenas, and jackals all inhabit the ranch, but
they harvest only a small share of the game.
The exact economic advantages of a game ranch over a cattle
ranch have not yet been determined. From the data the
Hopcrafts have gathered so far, it appears that the yield
of lean meat from an operation such as the game ranch will
be at least twice the poundage per acre taken from the best
cattle ranch in the region.
In addition to rapid growth rates in the game species, a
major reason for this higher productivity is that a variety
of herbivores partitioning resources can utilize much more
of the vegetation than cattle can.
An additional advantage of the game ranch is in the
potential for selling the hides. Those from the game should
have a much higher value than cowhides, but at the moment
the sale of game hides is prohibited by the Kenyan
government—quite properly, since most of them are obtained
by poaching. It is possible that a licensing system could
be devised to allow game ranchers to market their hides, as
mink ranchers do in the United States.
There are, of course, some problems still to be overcome.
The main difficulties involve breaking
traditions—traditions of what meat is good to eat,
traditions among scientists in animal husbandry for whom
the idea of game ranching is too novel, traditions among
African pastoral peoples such as the Masai, to whom cattle
are the main symbol of wealth.
In Africa, however, the benefits of breaking with these
traditions would be enormous. In the face of extremely
rapid human population growth, African game animals are
fast disappearing; even national parks are under intense
pressure from expanding agriculture and poaching. And
hunger is already widespread on the continent, which has
been stricken by disastrous droughts and famines in the
last few years. Food supplies per person in most African
countries south of the Sahara desert declined by about 10%
between 1970 and 1982, as population growth outstripped the
gains in food production. As the current drought has
deepened and spread, food production has plummeted by
another 10%. A major contributing factor to this
continent—wide tragedy has been desertification
caused in significant part by overgrazing of semiarid lands
by traditional domestic animals.
Clearly, game ranching could help preserve Africa's unique
large animals and contribute substantially to its food
supply—if it can become established before
desertification is too far advanced even to support the
game animals. We're happy to report that the Kenyan
government is very interested in the Hopcrafts' project,
and that more game ranches may be established in that
nation and elsewhere in Africa in the near future. The
Hopcrafts' ranch has been serving as a training ground for
interested students taking degrees in wildlife management
and animal husbandry. These students will eventually be
able to apply what they've learned to new projects.
Indeed, the Hopcrafts are now looking to the establishment
of a game ranch utilizing North American herbivores -deer,
antelope, American bison-in New Mexico, where overgrazing
of cattle has led to considerable desertification . In view
of its potential for being an ecologically benign,
sustainable, and productive system of food production in
any climatic region, we hope that game ranching is an idea
whose time has come.
People interested in the New Mexico game-ranching project
can get information by sending a self-addressed, stamped
envelope to US, Inc., Petosky, MI.
The Ehrlichs' work is supported in part by a grant from the Koret Foundation of San Francisco.