FREE ESSAY ON CHIMPANZEE

CHIMPANZEE

Chimpanzee
The acts of cannibalism and infanticide are very apparent in the behavior of the
chimpanzee. Many African studies show that wild chimpanzees kill and eat infants of their
own species (Goodall, 1986:151). Although there is not a clear answer why chimps engage
in this very violent and sometimes gruesome behavior there are many ideas and
suggestions. This essay will deal with chimpanzee aggression, cannibalism and
infanticide. This paper will present information on major research studies performed in
Africa and analyze how and why this strange behavior occurs in a commonly thought
peaceful primate.
Wild chimpanzees (Pan troglodytes schweinfurthii) are known to kill and eat mammals in
various parts of Africa. Monkeys were recorded to be consumed in the Gombe National Park,
the Kasakati Basin, and the Budongo Forest. Moreover, there is new evidence that
chimpanzees near the Ugalla River of western Tanzania also consume mammals (Riss,
1990:167). Cannibalism has also been recorded both in the Budongo Forest, Mahale
Mountains and the Gombe National Park.
In Jane Goodall's, May 1979 article in the National Geographic called Life and Death at
Gombe it reveals the first time that chimpanzees who were always perceived to be playful,
gentle monkeys, could suddenly become dangerous killers. I knew that some of our
chimpanzees, so gentle for the most part, could on occasion become savage killers,
ruthless cannibals, and that they had their own form of primitive warfare (Goodall,
1979:594). To try and explain this ruthless behavior it is necessary to first analyze
their social upbringing and unique lifestyle.
The Chimpanzee society is clearly a male dominated aggressive social unit. Males are
larger than females, they are more openly aggressive, and they fight more often
(Holloway, 1974:261).
These fights can look extremely fierce and
the victim screams loudly. But it is rare
for a fight between community members to last
longer than quarter of a minute, and it is
even more unusual for such a fight to result
in serious injury (Goodall, 1992:7).
Many fights break out suddenly. Afterwards the loser of the fight, even though clearly
fearful of the aggressor, will almost always approach him and adopt a submissive posture
(Goodall, 1992:8). The loser is giving in and admitting that he has lost and only feels
relaxed when the aggressor reaches out and gives what is called a reassurance gesture-he
will touch, pat, kiss or embrace the supplicator (loser) (Goodall, 1992:8).
Another example of chimpanzee aggression is the charging display. Although females
sometimes display this behavior, especially high ranking, confident females, it is
typically a male performance (Reynolds, 1967:82). During such a display, the chimp
charges flat out across the ground, slapping his hands, and stamping his feet. The chimps
hair then begins to bristle and his lips bunch in a ferocious scowl. He may pitch rocks
or jump around swinging branches (Strier, 1992:46). Essentially what he is doing is
making himself look bigger and more dangerous than he actually is, trying to intimidate
his opponents. We have found, over thirty years of study, that the young males who
display the most frequently, the most impressively, and with the most imagination, are
the most
likely to rise quickly to a high position in the male dominance hierarchy (Goodall,
1992:9).
In essence, every young male chimp is on a life long quest to become the top-ranking
position of the male hierarchy that is called the alpha-male. Many of the male
chimpanzees spend a lot of energy and run risks of serious injury in pursuit of higher
status. The rewards of the alpha male are claiming rights to the food, female partners,
and he also acquires a position exempt from attack by fellow chimps (Goodall, 1979:616).
However, the latter discussion has dealt solely with inter-group aggression, (fighting
within groups of the same community); outer-group aggression is grotesquely different.
A chimpanzee community has a home range within which its members constantly roam. Usually
the home range consists of roughly five to eight square miles. The adult male chimpanzees
usually in groups of three, take turns patrolling the boundaries of their area keeping
close together, silent and alert (Goodall, 1992:14). As they travel they pick up objects
sniffing them as if they are trying to find clues to locate strangers. If a patrol meets
up with a group from another community, both sides usually engage in threats, and then
are likely to retreat back to their home ground (Holloway, 1974:261). But if a single
individual is encountered, or a mother and a child, then the patrolling males usually
chase and, if they can, attack the stranger (Goodall, 1979:599). Ten very serious attacks
on mothers or old females of neighboring communities have been recorded in Gombe since
1970; twice the infants of the victims were killed; one other infant died from wounds
(Goodall, 1979:599).
In 1972 the chimpanzees of Gombe divided into two groups: the southern group (Kahama) and
the northern group (Kasakela). This was the start of what Jane Goodall called the four
year war. In 1974, a gang of five chimpanzees from the Kasakela community caught a single
male of the Kahama group. They hit, kicked, and bit him for twenty minutes and left him
bleeding from many serious wounds. A month later after this original occurrence another
prime Kahama male was caught by three chimps from Kasakela and severely beaten. A few
weeks later he was found, terribly thin and with a deep unhealed gash in his thigh. There
were three more brutal attacks leaving three more Kahama chimpanzees dead before 1977
(Goodall, 1979:606). By 1978 the northern males had killed all of the southern group and
took over both areas. It seems that we have been observing a phenomenon rarely recorded
in field studies-the gradual extermination of one group of animals by another, stronger,
group (Goodall, 1979:608). There is no clear reason for these brutal attacks to have
taken place unless that the dominant northern males before the community split, had
access to the southern community and they were just trying to attain their land back. We
know, today, that chimpanzees can be aggressively territorial (Goodall, 1992:14).
In August of 1975, Gilka a chimpanzee mother was sitting with her infant when suddenly
Passion, another mother appeared and chased her. Gilka ran screaming but Passion who was
bigger and stronger caught up, attacked, seized, and killed the baby. She then proceeded
to eat the flesh of the infant and share the gruesome remains with her adolescent
daughter, Pom and her infant son, Prof. This was the first observed instance of
cannibalistic behavior shown by Passion and Pom (Goodall, 1992:22). About a year after
this incident, Gilka gave birth to another infant and this time it was Pom who seized the
baby, but Passion and Prof again shared the flesh. There is no explanation why Passion
and Pom behaved as they did (Goodall, 1992:23).
Passion was always an asocial female, and
had been a very harsh mother to her own first
infant, Pom. It was only as Pom grew older
that the very close bond developed between
mother and daughter, and it was only because
the two acted with such perfect co-operation
that they were able to overcome some of the
other females of their community (Goodall, 1992:23).
During the years of their rampaging, a total of ten infants died or disappeared and every
instance point to Passion and Pom (Goodall, 1979:616). They would never try to attack a
female when there were any males around. Instead they would wait for the mother to be
alone with her infant and gang up on her. In three years from 1974 to 1976 only a single
infant in the Kasakela community had lived for more than one month. Finally, when Passion
gave birth again to a third child, and Pom also gave birth, the extraordinary
cannibalistic infant killing came to an end (Goodall, 1979:619).
Chimpanzees have been studied in the Mahale Mountains National Park for 25 years. The
study group, M-group, consisting of about 90 chimpanzees, has been monitored for 15
years. Cases reported from Mahale, Tanzania, are of special interest because adult males
kill and eat those infants that not only belong to the same community but are likely to
be their own offspring (Turner 1992:151).
On October 3, 1989, a case of within-group infanticide among Mahale
chimpanzees was observed.
"T. Asou, M. Nakamura and two cameramen of
a video team of ANC Productions Inc. from
Tokyo, and R. Nyundo of the Mahale Mountains
Wildlife Research Centre succeeded in
shooting most of the important scenes of the
infanticide and cannibalism (Nishida, 1992:152).
This is an example of the flagrant cannibalism and infanticide witnessed based on their
memos and videotape. During a chimpanzee group feeding period that had gone
unsuccessfully. Kalunde a 2nd-ranking male walked up to and snatched a six-month old
infant baby boy from the hands of its mother Mirinda. Kalunde ran with the infant on his
belly with Mirinda chasing after him screaming. Kalunde then hid in some vegetation until
two other males Shike and Lukaja found him and wanted to take the infant away from him.
Lukaja finally won a tug of war for the infant between the two other males and handed it
over to Ntologi the alpha male. Ntologi, who then dragged, tossed, and slapped it against
the ground climbed a tree with the infant in his mouth. He waved it in
the air, and finally killed it by biting it on the face. Then he proceeded to eat the
infant sharing the meat with the other chimps (Nishida, 1992:152). It is strange because
this sort of cannibalistic behavior is exactly like a group of chimpanzees feeding on the
meat of any mammal's dead carcass. Unfortunately, in this case though, it was the meat of
a dead chimpanzee infant. Nevertheless, after the infanticide, Mirinda was observed to
mate with Ntologi as well as Kalunde (Nishida, 1992:153). Even though both these males
assisted in the killing of her first infant.
Another example of this fierce and barbaric activity happened again on July 24, 1990,
M.B. Kasagula, a research assistant, observed five adult males including Ntologi
excitedly displaying (Nishida, 1992:153). Ntologi had his hand on a 5-month-old male
infant of Betty's. The infant was still alive. Ntologi began to bite on the infants'
fingers and then struck the infant against a tree trunk, and also dragged it on the
ground as he displayed. As a result the infant was killed (Nishida, 1992:153). Once
again, Ntologi shared the remains with ten adult females and eight males. Three hours
later the chimpanzees were still eating the carcass (Nishida, 1992:153).
Other than the two examples illustrated thus far, there were also five other cases of
Mahale Mountain within-group infanticides that were analyzed. Firstly, all the victims of
all seven cases were small male infants below 1 year of age (Hamai, 1992:155). Secondly,
infanticide also occurred mostly in the morning during an intensive feeding period
(Hamai, 1992:155). On six of the seven occasions, the captors of the infants were alpha
or beta males (Hamai, 1992:155). Group attacks were observed in at least three cases. In
all infanticide cases the mother persistently tried to recover her infant from the
adult males so long as it was still alive. However, an infant was only recovered by its
mother once (Hamai, 1992:157). Infants were killed while being eaten in all cases
(Nishida 1992:157). What appeared common in cannibalism but uncommon in predation was
that consumption of meat took a long time (*3 hr) and that the carcass-holder changed
frequently, considering the prey size and the number of consumers (Hamai, 1992:158). In
all cases of cannibalism, many chimps ate and shared the meat by recovering scraps. There
was always more than four adult male cannibals and the mother has never been seen to eat
meat from the carcass of her own offspring (Nishida, 1992:158). The Mahale Mountain study
provided an in-depth analysis on how the chimpanzees reacted during and after their
cannibalistic behavior.
There are several hypotheses explaining infanticide within a group of chimpanzees. One of
these being the male-male competition hypotheses. Nishida and Hiraiwa-Hasegawa (1985)
suggested that males of one clique destroy infants of females who associated with males
of a rival clique (Hamai, 1992:159). Spijerman (1990) proposed that infanticide functions
as a kind of display to fortify male social status, or to increase control over the
attention of others (Hamai 1992:159). Another idea was Kawanaka's (1981) that infanticide
was an elimination of the product of incest (Hamai 1992:159). Some believe that the
function of infanticide is to correct a female's promiscuous habit and coerce her into
more restrictive mating relationships with adult males, and especially with high ranking
males (Hamai, 1992:159). What is interesting in all of these examples of chimpanzee
infanticide is as soon as a chimpanzee male or female (Passion & Pom) got their hands on
an infant, the chimps surrounding them would suddenly become excited and want it
themselves as if the infant was just a piece of meat even though it was still alive.
In conclusion, there has been no evidence revealing why chimpanzees act and behave in
this cannibalistic fashion. There are many theories and ideas but like the theory of
evolution there is no one clear answer. Being the closest living relative to the human
being, chimpanzees exhibit complicated and intricate behavior due to their advanced
brains (Zuckerman, 1932:171). This paper has revealed that chimpanzees are creatures of
great extremes: aggressive one moment, peaceful the next. This gruesome violent behavior
can actually be linked to a similarity with human beings. It is widely accepted in the
scientific community that chimpanzees are the closest human relatives we have. If we are
indeed superior to these primates, does it not stand to reason that humans should be able
to learn from this violence and avoid it? Jane Goodall, in her article labeled, Life and
Death at Gombe draws a similar conclusion:
It is sobering that our new awareness of
chimpanzee violence compels us to acknowledge
that these ape cousins of ours are even more
similar to humans than we thought before.
Bibliography
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Press.
Goodall, Jane. 1986 The Chimpanzees of Gombe. Harvard University Press, Cambridge, Mass
Reynolds, Vernon, 1967. The Apes. New York, NY: E.P. Dutton.
Strier, K. B. 1992. Faces in the Forest: The Endangered Muriqui Monkeys of Brazil. Oxford
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