Chimpanzee Cannabalism And Infanticide Essay, Research Paper
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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 mammals 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 which 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 is 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 females 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.