94 CHAPTER 4 | Primate Behavior
Annually, chimpanzee hunting parties at Gombe kill
about 20 percent of these monkeys, many of them ba-
bies, often shaking them out of the tops of 30-foot trees.
They may capture and kill as many as seven victims in a
raid. These hunts usually take place during the dry sea-
son when plant foods are less readily available and when
females display genital swelling, which signals that they
are ready to mate. On average, each chimp at Gombe eats
about a quarter-pound of meat per day during the dry
season. For female chimps, a supply of protein-rich food
helps support the increased nutritional requirements of
pregnancy and lactation.
Somewhat different chimpanzee
hunting practices have been ob-
served in West Africa.
At Tai National Park
in the Ivory Coast, for
instance, chimpanzees
engage in highly coor-
dinated team efforts to
chase monkeys hiding
in very tall trees in the
dense tropical forest.
Individuals who have
especially distinguished
themselves in a success-
ful hunt see their contri-
butions rewarded with
more meat.
Recent research shows that bonobos in Congo’s rain-
forest also supplement their diet with meat obtained
by means of hunting. Although their behavior resem-
bles that of chimpanzees, there are crucial differences.
Among bonobos, hunting is primarily a female activity.
Also, female hunters regularly share carcasses with other
females, but less often with males. Even when the most
dominant male throws a tantrum nearby, he may still
be denied a share of meat.^26 Female bonobos behave in
much the same way when it comes to sharing other foods
such as fruits.
While it had long been assumed that male chimpan-
zees were the primary hunters, primatologist Jill Pruetz
and her colleagues researching in Fongoli, Senegal, doc-
umented habitual hunting by groups of young female
and male chimpanzees using spears.^27 The chimps took
spears they had previously prepared and sharpened to a
point and jabbed them repeatedly into the hollow partsAlthough gorillas (like bonobos and chimps) build
nests, they are the only one of the four great apes that have
not been observed to make and use other tools in the wild.
The reason for this is probably not that gorillas lack the in-
telligence or skill to do so; rather, their easy diet of leaves
and nettles makes tools of no particular use.
Hunting
Prior to the 1980s most primates were thought to be veg-
etarian while humans alone were considered meat-eating
hunters. Among the vegetarians, folivores were thought to
eat only leaves while frugivores feasted on fruits. Though
some primates do have specialized adaptations—such as
a complex stomach and shearing teeth to aid in the diges-
tion of leaves or an extra-long small intestine to slow the
passage of juicy fruits so they can be readily absorbed—
primate field studies have revealed that the diets of mon-
keys and apes are extremely varied.
Many primates are omnivores who eat a broad range
of foods. Goodall’s fieldwork among chimpanzees in
their natural habitat at Gombe Stream demonstrates
that these apes supplement their primary diet of fruits
and other plant foods with insects and meat. Even more
surprising, she found that in addition to killing small in-
vertebrate animals for food, they also hunt and eat mon-
keys. Goodall observed chimpanzees grabbing adult red
colobus monkeys and flailing them to death. Since her
pioneering work, other primatologists have documented
hunting behavior in baboons and capuchin monkeys,
among others.
Chimpanzee females sometimes hunt, but males do
so far more frequently. When on the hunt, they may
spend hours watching, following, and chasing intended
prey. Moreover, in contrast to the usual primate practice
of each animal finding its own food, hunting frequently
involves teamwork to trap and kill prey, particularly
when hunting for baboons. Once a potential victim has
been isolated from its troop, three or more adult chimps
will carefully position themselves so as to block off es-
cape routes while another pursues the prey. Following
the kill, most who are present get a share of the meat,
either by grabbing a piece as chance affords or by beg-
ging for it.
Whatever the nutritional value of meat, hunting is
not done purely for dietary purposes, but for social and
sexual reasons as well. Anthropologist Craig Stanford,
who has been doing fieldwork among the chimpanzees
of Gombe since the early 1990s, found that these sizable
apes (100-pound males are common) frequently kill ani-
mals weighing up to 25 pounds and eat much more meat
than previously believed. Their preferred prey is the
red colobus monkey that shares their forested habitat.
Gulf of
Atlantic Ocean GuineaMALICÔTE D’IVOIRETai
National
LIBERIA ParkGUINEAGHANABURKINA
FASO(^26) Ingmanson, E. J. (1998). Comment. Current Anthropology 39, 409.
(^27) Pruetz, J. D., & Bertolani, P. (2007, March 6). Savanna chimpanzees,
Pan troglodytes verus, hunt with tools. Current Biology 17, 412–417.