There
are two species of chimpanzee, the common chimpanzee, Pan troglodytes
- which is described in this fact sheet - and the very rare
and endangered bonobo or pygmy chimpanzee, Pan paniscus. Both
belong to the Hominidae family which also contains the other
species of apes and humans. The bonobo are approximately half
the weight of the common chimpanzees, but are otherwise not
easily distinguishable.
The
common chimpanzee has a wide distribution, across west and central
Africa to Uganda in the east. There are estimated to be 191,000
wild chimpanzees in Africa. However, many are fragmented into
small populations which makes it difficult for individuals to
transfer between groups. Chimpanzees are listed on Appendix
I of CITES - the Convention on International
Trade in Endangered Species, which means that any
international trade of chimps or their parts is illegal.
Chimpanzees
are intelligent and playful animals and they spend 45-60% of
their time feeding, 25-39% of their time resting or grooming
and 8-20% of their time travelling. They are primarily forest
living animals, but they also inhabit forest-savana mosaic,
woodland and even dry savana.
Female
chimpanzees are pregnant for eight months and usually give birth
to a single baby, twins are born at the same frequency as human
babies. A baby will be dependant on its mother for four years,
after it is weaned there is still a strong bond between the
mother and her infant until it reaches seven or eight years
of age. Females are ready to reproduce at about thirteen years
old and males at fifteen years. Adult chimpanzees weigh 30-50
kg and they live up to forty five years.
Chimpanzees
are extremely social animals living in groups, or communities,
of 20-100 individuals with both males and females of all age
classes. Females tend to outnumber males. When they are mature,
male chimpanzees tend to stay with the groups in which they
were born and it is the females that transfer to new groups
to meet unrelated males. As they remain together for many years,
very strong social bonds are formed between the males. They
sometimes co-operate when they are hunting and they spend a
lot of time
grooming each other.
Adult
females are not as sociable as the males, and although not a
lot is know about their social relationships it is believed
that the older females are generally dominant to the younger
ones. New females are lowest in the ranks when they first join
a new group.
The
dominance relationships are more complex in the males, although
age is a good indicator of rank as adolescent males are dominated
by the adults. As they mature the status of males increases,
they are described as low, middle and high ranking. The highest
rank that males can achieve is called alpha status which they
typically reach around twenty to twenty-five years of age. Not
all males reach alpha status, and as well as age it is influenced
by size, physical condition and personality traits.
At
any one time there is typically only one male holding the most
dominant rank and he shows high levels of aggression towards
the others. Aggressive behaviour between individuals does not
normally lead to physical violence. The alpha male travels with
his hair slightly erect and his shoulders frequently hunched
to appear larger than he is, he typically holds the rank for
three to ten years.
Chimpanzees
are omnivorous. They forage both in the trees and on the ground,
their diet is made up mainly of fruit and leaves, and is supplemented
with nuts and seeds. Seasonal variation in availability governs
the amount of the different types of food eaten. Meat is also
eaten when it is available including ants, termites, caterpillars
and occasionally small mammals such as antelopes and monkeys.
Chimpanzees sometimes hunt for themselves or they steal prey
from other predators. Meat is quite a prized food and it is
usually the adult males who get the greatest amount, although
they will sometimes share it with others who are prepared to
grovel as well as females that they like.
When
feeding on ants and termites chimpanzees sometimes use tools.
They use sticks which they modify by removing any leaves and
offshoots and adjusting them to the correct length, they then
poke the stick into the ants' nest or termite mount. The soldier
ants or termites that are protecting the nests from invasion
stream up the stick and the chimpanzee then eats them from the
stick. By doing this the chimpanzee is able to reduce the number
of painful bites it receives from the very defensive insects.
The females seem to be better at this skill than males.
Tool
use is also observed for cracking nuts. Some groups use an 'anvil'
which tends to be a protruding tree root on which they place
the nut before striking it with a large rock. All tool use requires
practice before perfection is achieved and young chimpanzees
spend time watching their parents before attempting it themselves.
Water is drunk when available, either by dipping the mouth directly
into the water, or by using naturally occurring containers such
as scoop-shaped dead leaves. Chimpanzees are also able to obtain
water from holes inside trees, which provides an addition source
of water during the dry season. They may either insert their
whole head, insert their hand and then lick off the wetness
or use a handful of leaves to act as a sponge.
Threats
to Chimps
The greatest threat to chimpanzees is that posed by humans.
Chimpanzees are heavily poached in many countries, even where
they are legally protected. The spread of agriculture and timber
extraction is now a problem throughout the species' range, and
has increased the risk of hunting in areas where they were previously
inaccessible - which helped to keep the primates safe.
Chimpanzees
are hunted for several reasons. Babies are taken from their
mothers in the wild for the pet trade both in their native countries
and in the West. They are also taken for theentertainment industry,
and for scientific and pharmaceutical research, although many
of the individuals involved with this are now bread in captivity.
Adults are not taken as they are too dangerous to handle, often
the babies are so young that they have not learnt the skills
they need to look after themselves. Unfortunately, when the
babies grow into adults their owners very often find it difficult
to cope with them and they are often dumped. Adults are killed
to provide momentoes for tourists and for the bush-meat trade.
Disease
has also been implicated as an important cause of death in chimpanzees
especially in those captured for the pet trade or entertainment
industry. They also suffer from malnutrition and dehydration
as they are not properly cared for when they are transported.
Protecting Chimps
There have been several long term studies into the behaviour
of chimpanzees. Much is now known about all aspects of their
ecology and social behaviour. This knowledge is vital for many
projects concerning their protection. Captive breeding and rehabilitation
projects sometimes involve teaching the chimpanzees the skills
that they need to survive in the wild, for example they have
to be able to recognise what fruits and leaves are edible, they
need to learn how to build nests to sleep in and they need to
learn how to avoid
predators.
How
We Help:
Bill Jordan Wildlife Defense Fund USA supports the conservation
and welfare of chimpanzees through its association with Sweetwaters
Chimpanzee Sanctuary in Kenya. The sanctuary is a place of rescue
and shelter for orphaned chimpanzees where they are able to
enjoy the companionship of their own kind whilst they learn
how to play, explore and climb in their natural habitat.
Initially individuals brought into the sanctuary often require
a lot of attention from the keepers, but in time become more
independent. Unfortunately they are unable to be returned to
the wild but through BJWDF USA's adoption scheme we are able
to provide funds that go towards their long term care.