Chimpanzees As
Neighbors
Chimpanzees and
humans both live in communities but these communities can be very
different from each other.

Chimpanzee
communities can consist of about 20-100 chimps whereas human
communities can be found in the millions, but each human and
chimpanzee community may have smaller groups. Chimpanzee groups live
in selected territories, similar to humans who live in different
communities in different countries. Think about it like this: if you live
in New York State, you could say you live in the group called New
York but you are part of the larger community and territory of the
United States. However, chimpanzee’s territories are much smaller
than ours; only consisting of 30-150 square miles. That is as big as
50-250 football fields! Territories consist of two different areas:
the border and the core. A border or peripheral area of a territory
is the outside area of the community. The core area of a territory
is in the middle of the territory and is the most heavily used
portion of the territory.
The
main factors which affect a chimpanzee’s territory size are food
availability and intercommunity relations. Chimpanzees are a very
social species within their communities. It is important for
communities to have strong social bonds with each other to ensure
their welfare. However, such hospitality does not usually extend to
neighboring communities. Chimpanzees are very territorial and
protective. Males and sometimes females and juveniles go on
'patrols' to ensure other chimpanzees do not enter their territory.
These patrols are usually a single line of chimpanzees that walk
along their territory’s border. These patrols are similar to a
community watch in humans, where people keep an eye out for each
other to make sure there are no intruders that can harm them walking
around their neighborhood. There are some differences between human
societies and chimp societies. When human communities are threatened
we call the cops; chimpanzees on the other hand will attack the
intruder if the situation calls for such action. If the patrollers
are too few in number they will retreat back to their core
territory, but if they outnumber the intruders a fight usually is
started. The fight ends when the intruders leave. If the intruders
don’t leave then a war may be started between two communities. When
a community wins a war they receive similar rewards that early
humans received when they went to war. The victors
gain land and territory, new food sources, and other resources. The
victors also get improved security and strength by adding numbers to
their group. The addition of more females leads to more chimpanzees
in the community and more genetic diversity. Besides all of these
benefits new research shows that when there is more territory,
females become bigger and have a more births, thus increasing
population by decreasing the time it takes to produce offspring.
There are
differences in chimpanzee communities between who can immigrate and
who cannot and how a new chimp is accepted into a new community.
Males do not immigrate because males don’t allow males from other
communities to join their troupe. If a new male tries to join a
troupe he will be fought off. So, males typically remain in their
original group, however females leave their communities at
adolescence, which is around 9-14 years old. When a new female
enters a community they are generally accepted by males but resident
females are not as happy with the new female. A female that is old
enough to have a baby will be welcomed and protected by the males,
but the other females of the group may try and attack her. These
females want to protect their status because the younger immigrant
females could outrank them and end up getting more food and better
nesting sites. It has been speculated that females leave the
community because of negative social developments and availability
of energy for dispersal, not in search of mates. Regardless of why
the female leaves, it is in fact a good thing for her that she does.
When she leaves she increases genetic diversity of wild chimps.
Message from CAC'ers
We hiked for miles and miles within the
territory of only one community of chimpanzees just to see
some of them. This long hike showed us just how big their
range really was. Later on, after all that hiking, when we
returned to camp we saw the same chimpanzees miles from when
we first spotted them!
|
|