Communication and Learning 93Chimpanzees also use plants for medicinal purposes,
illustrating their selectivity with raw materials, a quality
related to tool manufacture. Chimps that are ill by outward
appearance have been observed to seek out specific plants
of the genus Aspilia. They will eat the leaves singly without
chewing them, letting the leaves soften in their mouths for
a long time before swallowing. Primatologists have discov-
ered that the leaves pass through the chimp’s digestive sys-
tem whole and relatively intact, having scraped parasites
off the intestine walls in the process.mother; only later does the desire to feed on the tasty nut-
meat take over.^23
Use of Objects as Tools
A tool may be defined as an object used to facilitate some
task or activity. The nut cracking just discussed is the most
complex tool-use task observed by researchers in the wild,
involving both hands, two tools, and exact coordination.
It is not, however, the only case of tool use among apes
in the wild. Chimpanzees, bonobos, and orangutans make
and use tools.
Here, a distinction must be made between simple tool
use, as when one pounds something with a convenient
stone when a hammer is not available, and tool making,
which involves deliberate modification of some mate-
rial for its intended use. Thus otters that use unmodified
stones to crack open clams may be tool users, but they are
not toolmakers. Not only do chimpanzees modify objects
to make them suitable for particular purposes, but chimps
also modify these objects into regular and set patterns.
They pick up and even prepare objects for future use at
some other location, and they can use objects as tools to
solve new problems. Thus chimps have been observed us-
ing stalks of grass, twigs that they have stripped of leaves,
and even sticks up to 3 feet long that they have smoothed
down to “fish” for termites. They insert the modified stick
into a termite nest, wait a few minutes, pull the stick out,
and eat the insects clinging to it, all of which requires con-
siderable dexterity. Chimpanzees are equally deliberate in
their own nest building. They test the vines and branches
to make sure they are usable. If they are not, the animal
moves to another site.
Other examples of chimpanzee use of tools involve
leaves, used as wipes or as sponges, to get water out of a
hollow to drink. Large sticks may serve as clubs or as mis-
siles (as may stones) in aggressive or defensive displays.
Twigs are used as toothpicks to clean teeth as well as to
extract loose baby teeth. They use these dental tools not
just on themselves but on other individuals as well.^24
In the wild, bonobos have not been observed making
and using tools to the extent seen in chimpanzees. How-
ever, the use of large leaves as trail markers may be consid-
ered a form of tool use. That these animals do have further
capabilities is exemplified by a captive bonobo who has
figured out how to make tools of stone that are remarkably
like the earliest such tools made by our own ancestors.^25
Chimps use a variety of tools in the wild. Here a chimp is using a
long stick stripped of its side branches to fish for termites. Chimps
will select a stick when still quite far from a termite mound and
modify its shape on the way to the snacking spot.(^23) de Waal, The ape and the sushi master.
(^24) McGrew, W. C. (2000). Dental care in chimps. Science 288, 1747.
(^25) Toth, N., et al. (1993–2001). Pan the tool-maker: Investigations into the
stone tool-making and tool-using capabilities of a bonobo (Pan panisicus).
Journal of Archaeological Science 20 (1), 81–91.
© Martin Harvey/Peter Arnold, Inc.
tool An object used to facilitate some task or activity.
Although tool making involves intentional modification of
the material of which it is made, tool use may involve objects
either modified for some particular purpose or completely
unmodified.