Pan Africa NewsThe Newsletter of the Committee for the Careand Conservation of Chimpanzees, and theMahale Wildlife Conservation Society
JUNE 2003
P.A.N. EDITORIAL STAFF
Chief Editor:
Toshisada Nishida, Kyoto University, Japan
Associate Editors:
Christophe Boesch, Max-Planck Institute, Germany
Jane Goodall, Jane Goodall Institute, USA
Takayoshi Kano, Kyoto Sangyo University, Japan
Tetsuro Matsuzawa, Kyoto University, Japan
William C. McGrew, Miami University, USA
John C. Mitani, University of Michigan
Vernon Reynolds, Oxford University, UK
Yukimaru Sugiyama, Tokai-Gakuen University, Japan
Shigeo Uehara, Kyoto University, Japan
Richard W. Wrangham, Harvard University, USA
Editorial Secretaries:
Noriko Itoh, Kyoto University, Japan
Koichiro Zamma, Kyoto University, Japan
Michio Nakamura, Japan Monkey Centre, Japan
Kazuhiko Hosaka, Kamakura Women’s University, Japan
Michael A. Huffman, Kyoto University, Japan

Instructions to Authors:
Pan Africa News publishes articles, notes, reviews,
forums, news, book reviews, letters to editor, and classifiedads (restricted to non-profit organizations) on any aspect ofconservation and research regarding chimpanzees andbilias. Contributors are requested to write in English andpapers except forum and reviews should usually be 1,000
words or less. Manuscripts should be submitted by e-mailto:
PAN@jinrui.zool.kyoto-u.ac.jp
Photos and figures, however, should be sent by air
mail to: T. Nishida, Dept. of Zoology, Graduate School of
Science, Kyoto University, Kitashirakawa- Oiwakecho,
Sakyo, Kyoto, Japan.
Publication of the next issue will be December 2003.
Deadline for manuscripts is the end of November.

Gombe Health Guidelines Proposed.
Researchers as well as tourists and park staff might
unwillingly transmit infectious diseases to wild
chimpanzees. Everybody who approaches habituatedchimpanzees closely should take every care not to hurt
chimpanzees. Gombe researchers are proposing theVOL. 10, NO. 1

Contents<FORUM>
Health guidelines for visiting researchers in Gombe
National Park to minimize risk of disease transmission
among primates (Updated 8/01/03).
By Anthony Collins 1<REVIEW>
Field research at Ngogo, Kibale National Park,Uganda.
By John Mitani & David Watts 3<REVIEW>
Acquisition of skilled gathering techniques in Mahale
chimpanzees.
By Richard W Byrne & Nadia Corp 4<NOTE>A case of infant carrying by an adult male chimpanzee
in the Budongo Forest.
By H. Notman & J. Munn 8<NOTE>
Eleven-year old male chimpanzee outranks ex-alphaadult male at Bossou.
By Michio Nakamura & Gaku Ohashi 9<NOTE>A note on the southern neighboring groups of M groupin the Mahale Mountains National Park.
By Masaki Shimada 12<NOTE>
Evidence for leaf swallowing behavior by savanna
chimpanzees in Senegal- a new site record.
By Jill D. Pruetz & Susannah Johnson-Fulton 15<FORUM>
Health Guidelines for Visiting
Researchers in Gombe National
Park to Minimize Risk of
Disease Transmission amongPrimates (Updated 8/01/03)

following guidelines as the materials for further
discussion. We welcome your comments (ed.):Anthony Collins
Jane Goodall InstitutePrinted on recycled paper

2

Pan Africa News, 10(1), June, 2003

A) Before coming to Gombe, researchers
are requested to:following and observation distance of 7.5
meters (25 feet).
If quarantine measures were not followed,
maintain a distance of at least 10m (33 ft)
and a maximum observation limit of one
hour per habituated chimpanzee or groupper day.
3. Be aware that the number of observers
with any habituated chimp or chimp
group should not exceed six people. If
there is a conflict of interest when chimp
parties join-up, let non-essential
assistants be prepared to withdraw till thechimps separate again. Also, when a partyof tourists arrive, be prepared to give thempriority for their one hour.
4. Control sneezing and coughing while
following and observing chimpanzees. No
spitting or nose-blowing on the ground.
5. If you need a latrine and one is not nearby,
dig a foot deep hole for burying feces
6. Never smoke or eat in the forest. While
preparing and eating food at home, do notleave remnants outside for wild animals to
consume, and never feed them. Baboons
can become aggressive when trying tosteal food .. it is better if they do not see it.
7. Carry equipment, backpacks and otheritems at all times, don't put them down.
Both chimpanzees and baboons will steal
anything left unattended. Such items, aswell as tissues and bandannas, arepossible carriers of infectious pathogens.
8. Never litter. Throwing food, candy
wrappers, cigarette butts or any otherwaste onto the ground is forbidden. Waste
items may be infectious.
9. Do not attempt flash photography or useof reflective devices. Never try to attract
an animal’s attention in order to take abetter photograph or video.
10. Speak quietly. Do not use arm gestures
while talking or move suddenly. Neverlook baboons directly in the eye as it islikely to be interpreted as a threat.
11. Never spread out or form a full or partial
circle around animals being observed.
12. At home, do not leave clothing or otherpersonal items unattended outside

1.

2.
3.

4.

Obtain current immunization against:
yellow fever (10 years protection)(lifetime protection)
polio
tetanus(booster every 5 years
questionable time)
hepatitis A (lifetime protection-questionable time)(lifetime protection)
measlesmeningitis (3 years protection)
Ensure clear TB status (negative skin test)
or vaccine for TB (10 years protection).
Researchers from temperate-zone
countries are please to obtain (same year)
immunization against influenza in winter(October through March in the Northernhemisphere, April through September in
the Southern hemisphere).
Ensure clear internal parasite status.

B) Upon arrival at Gombe, researchers
are requested to:
1.
2.

3.

4.

5.

Provide proof of vaccinations.
Remain quarantined for 5-7 days before
entering the forest and following
chimpanzees and baboons.
Pass physical exam with GSRC staff nurse.
People with illnesses are forbidden toenter the forest or follow chimps andbaboons on the beach.
Attend a sensitization session upon arrivaland sign the health and safety regulation
guidelines.
Adhere to regular health checks during
research visit.

C) Before entering forest, visiting
researchers are advised to:
1.
2.
3.

Use the latrine before entering the forest.
Wash hands before entering the forest andupon return.
Disinfect soles of field shoes in antiseptic
bath of 2% chlorine solution.

D) During chimp follows, visiting
researchers are advised to:1.

2.

Ensure you are not sick: do not enter theforest and follow chimpanzees andbaboons if sick.
Maintain the mandatory minimum

Pan Africa News, 10(1), June, 2003
You are responsible for the behaviour of people
who work for you, cooks and guides: please
educate them in ways to reduce the risk of
disease transmission.
These guidelines are subject to improvement andwe will welcome your suggestions.

<REVIEW>
Field Research at Ngogo, Kibale
National Park, Uganda
John Mitani, University of Michigan
David Watts, Yale University
David Watts initiated fieldwork on thecommunity of chimpanzees at Ngogo, Kibale
National Park, Uganda, during two months inthe summer of 1993. This followed pioneeringobservations carried out by Michael Ghiglieri (1)in 1976 – 1977 and subsequent study by Bettina
Grieser-Johns (2) in 1992 – 1993. John Mitani
returned with Watts to Ngogo in June 1995.
Since that time we have been assisted by ourstudents and Jeremiah Lwanga, Martin Muller,
and a team of 4 – 5 Ugandan research assistantsin our effort to maintain continuous observationsof the Ngogo chimpanzees.
The unusual demographic size and structureof the Ngogo chimpanzee community furnish partof the impetus for our studies. With over 70
adult males and females and approximately 150
individuals, this community is the largest thathas been reported thus far in the wild. As theresult of the extremely large number of males,
the Ngogo chimpanzees hunt often and with an
unusual degree of success (3). Male chimpanzees
at Ngogo also frequently patrol the boundary of
their territory (4). This behavior has led toseveral documented cases of lethal intergroupaggression (5-6 and Watts & Mbabazi
unpublished data). Our observations have also
revealed that male chimpanzees at Ngogo
sometimes adopt novel coalitionary matingtactics (7) and have shown that males who belong
to the same age cohort and who are close indominance rank affiliate and cooperate

3
non-randomly (8). Other work has contributed to
our understanding of why chimpanzees hunt andshare meat (9) and has furnished insights into
the intriguing evolutionary processes ofreciprocity and interchange (10).
Along with our students, we continue to build
on our prior work at Ngogo by conducting
investigations on several topics. In previous
research, we have shown that kinship may notplay an important role in structuring aspects ofmale social relationships (8, 11). These studies
have thus far been limited to information on
mitochondrial DNA. In work conducted incollaboration with Linda Vigilant and UniversityofMichigan
graduatestudent
Kevin
Langergraber, we are using samples collected
non-invasively in the field to obtain better
estimates of genetic relatedness between males.
Data derived from nuclear genetic markers will
permit us to examine in greater detail the effectof kinship on various aspects of male chimpanzee
social behavior. After a brief hiatus in research(12), we are returning to the study of chimpanzee
vocal behavior with an investigation focused on
uncovering the factors that affect acoustic
variation between and within individuals. This
research will be conducted by Michigan graduate
student, Anne Fowler. In a study completed with
Michigan graduate student, Sylvia Amsler, wehave demonstrated that male chimpanzees at
Ngogo form social bonds above the level of dyadic
pairs (13). Two subgroups of males can be definedat Ngogo based on their tendency to associate in
temporary parties. Members of both subgroups,
however, range together over the entire territory,
and nothing suggests that the community willfission. Amsler will carry out additional researchon how the Ngogo chimpanzees use theirterritory.
To date, most of our research has focused on
adult male chimpanzee behavior. Yale University
graduate students, Hogan Sherrow and Monica
Wakefield, are currently in the field conducting
observations of adolescent male and adult female
chimpanzees, respectively. Their work promises
to fill several gaps in knowledge and enrich ourunderstanding of the Ngogo community ofchimpanzees. The Ngogo chimpanzees are very
well-known for their hunting behavior (14).

4

Pan Africa News, 10(1), June, 2003

Long-term data suggest that the red colobus
population at Ngogo has suffered a decline in
numbers since 1976 (15). Whether this decline
can be attributed to chimpanzee predation is
unknown. Yale University graduate student
Simone Teelen has completed fieldwork toaddress this and related questions by studying
the effects of chimpanzee predation on the
behavior of red colobus monkeys at Ngogo.
As we enter our ninth continuous year of fieldresearch, much remains to be done. In future
work, we plan to address some open questions
regarding meat sharing and male mating
behavior and social strategies. Along with our
Ugandan postdoctoral associate Jeremiah
Lwanga and Yale graduate student Kevin Potts,
we will continue work on feeding ecology andbehavior. Potts plans to examine the foraging
strategies employed by the Ngogo chimpanzees.
Lwanga’s ongoing studies of forest ecology will be
combined with data on chimpanzee feeding
behavior and habitat use to address why the
Ngogo community is so large. During the past
year, we have witnessed four more cases of lethal
aggression at Ngogo. In contrast to priorobservations, one of these took place within the
Ngogo community. We will describe details ofthese attacks in future reports.

References
(1)
(2)

(3)

(4)

(5)

(6)

(7)

(8)

Ghiglieri M 1984. The chimpanzees of the Kibale
forest. Columbia University Press, New York.
Grieser-John B 1996. Responses of chimpanzees
to habituation and tourism in the Kibale Forest,
Uganda. Biol Conserv 78: 257-262.
Mitani J, Watts D 1999. Demographic influenceson the hunting behavior of chimpanzees. Am J
Phys Anthrop 109: 439-454.
Watts D, Mitani J 2001. Boundary patrols andintergroup encounters in wild chimpanzees.
Behaviour 138: 299-327.
Watts D, Mitani J 2000. Infanticide andcannibalism by male chimpanzees at Ngogo,
Kibale National Park, Uganda. Primates 41:
357-365.
Watts D, Mitani J, Sherrow H 2002. New casesof inter-community infanticide by malechimpanzees at Ngogo, Kibale National Park,
Uganda. Primates 43: 263-270.
Watts D 1998. Coalitionary mate-guarding by
male chimpanzees at Ngogo, Kibale National
Park, Uganda. Behav Ecol Sociobiol 44: 43-55.
Mitani J, Watts D, Pepper J, Merriwether DA

(9)
(10)

(11)

(12)

(13)

(14)

(15)

2002. Demographic and social constraints onmale chimpanzee behaviour. Anim Behav 63:
727-737.
Mitani J, Watts D 2001. Why do chimpanzees
hunt and share meat? Anim Behav 61: 915-924.
Watts D 2002. Reciprocity and interchange inthe social relationships of wild malechimpanzees. Behaviour 139: 343-370.
Mitani J, Merriwether DA, Zhang C 2000a. Maleaffiliation, cooperation, and kinship in wild
chimpanzees. Anim Behav 59:885-893.
Mitani J, Hunley KL, Murdoch ME 1999.
Geographic variation in the calls of wild
chimpanzees: A re-assessment. Am J Primatol
47: 133-152.
Mitani J, Amsler S (in press). Social and spatialaspects of male subgrouping in a community ofwild chimpanzees. Behaviour
Watts D, Mitani J 2002. Hunting behavior ofchimpanzees at Ngogo, Kibale National Park,
Uganda. Int J Primatol 23: 1-28.
Mitani J, Struhsaker T, Lwanga J 2000b.
Primate community dynamics in old growthforest over 23.5 years at Ngogo, Kibale National
Park, Uganda: implications for conservation andcensus methods. Int J Primatol 21:269-286.

<REVIEWS>
Acquisition of Skilled Gathering
Techniques in Mahale
Chimpanzees
Richard W Byrne & Nadia Corp

School of Psychology, University of St Andrews,
Scotland U.K.

Chimpanzees show a remarkable ability toorganize actions into complex programs, shown
most famously in their ability to employ tools inmany different ways for subsistence. Chimpanzee
tool use has been much studied, with anemphasis on the tool rather than the process ofuse. We planned instead to examine chimpanzee
skills in the broader context of plant-processing
techniques, with an emphasis on the process. In
particular, we focused on the development of
infants in parallel with describing the skills of
their mothers. Data were collected from M groupchimpanzees in the Mahale Mountains National
Park during February–December 1998 and thenagain June 1999–January 2000. Focal samplingPan Africa News, 10(1), June, 2003
procedures were used to collect data on 14
mother-infant pairs, with 10x40 binoculars to
help see the fine details and action sequences
recorded on Dictaphone for later transcription.
Central to our work is the measurement of‘complexity’ and the degree to which the hands of
non-human great apes constrain their cognitive
capacities. Several possible measures ofcomplexity, even ones which might have been
expected to ‘trade off’ against each other (e.g. sizeof action repertoire, and the mean number ofsuch actions used for any given task), do in factprovide converging evidence of complexity (1).
Many food plants used by Mahale chimpanzees
were relatively simple for them to consume
without elaborate techniques. However, complex
plant gathering was shown in two circumstances:(1) embedded foods, e.g. pulp from tough-shelled,large fruits; and (2) physically defended leaves,
where defences had to be circumvented in orderto feed painlessly. In both cases, the techniques
employed showed considerable manual dexterity(2), and hierarchical organization (1, 3).
Since leaf-processing varies from simple
mouthing to a quite complex task, we were able
to
make
a
directtestofthehypothesis—often-assumed—that
complexcognition is primarily valuable for difficult
manual tasks. We compared processing of 8 leaf
foods which differed in this way, and strongly
confirmed this hypothesis: complex foodprocessing may therefore have selected forcognitive
advanceinthesharedchimpanzee/human line of ancestry (4).
Of cardinal interest was to examine acquisitionof skill. The clearest developmental sequence weobtained was for the processing of an embedded
food, Saba florida. Many of the developmental
changes were explicable in terms of chimpanzee
maturation: increasing power, reach and manual
dexterity with age of infant (5). However, some
aspects hinted that social learning mechanisms
might also be involved: for instance, we observedsome cases where the infant intently watched themother or another older individual as they fed,
frequent synchronized feeding with the mother,and numerous cases of both food solicitation andfood sharing. All these circumstances might aid
acquisition of complex skills—but did they? We

5suggest a more conservative evaluation.
Young infants typically depended on theirmothers for access to the edible parts of Saba.
This means that synchronized feeding, intense
observation, and food solicitation may reflect nomore than an infant’s strong motivation to gain
food. Social learning cannot therefore beconcluded to be necessary from observation ofthese behaviours, although it often has been in
the past. Food sharing, similarly, does not meanthat the mother is deliberately sharing
knowledge with the infant. We found thatsolicitation peaks very early in the infant’s life, at
a time when lactation is still essential, andmothers share little food at that time. Later indevelopment, when the infant would be able togain significant nutrition from solid food, mothers
share food virtually on demand. This is mostparsimoniously explained as a consequence of amother optimizing her energy budget. Whensharing solid food can aid in reducing lactational
demands on the mother, she shares; but not
before then, when the infant is most in need ofknowledge. Thus, we do not consider thatchimpanzee food sharing evolved with a primaryfunction of passive tutoring. But, as aconsequence of these factors—the infant’s desire
for food, and the mother’s optimization of energy
transfer to the infant—the learning process forthe infant may nevertheless be “scaffolded” (6, 7).
If relevant information is indeed gained throughthe infant’s (hunger-motivated) observations, andthe mother’s (energy optimization) food-sharing,
this is most likely to involve mechanisms which
do not imply any intent on behalf of the motheror infant, such as affordance learning (8) or
imitation without intentionality (9, 10). We foundno evidence to support the idea that teaching (11)or imitation in the sense of gestural copying (12,13) were involved in the acquisition of this rather
complex natural task.
An unexpected finding was that, whenprocessing Saba and Citrus fruits, chimpanzees
show strong manual laterality which varies in
direction between the sexes (14). It is generally
accepted that laterality is elicited by a need forskilled manipulation （15-17）, so our finding ofstrong individual hand preferences provides
orthogonal evidence that chimpanzees see these6tasks as cognitively challenging.
However, the sex-linked pattern ofmanual laterality among thechimpanzee population is unique,as far as we know. Moreover, it
may shed light on the origins of
the sex difference found in modern
day humans, where males are on
average slightly more left-handedor ambidextrous than women.
When they handle Saba or
Citrus fruits bimanually, Mahale
chimpanzees first grip the whole
fruit by laying one hand overanother in an extra-strong grip;
the choice of hand to apply first ishighly lateralized and correlates
positively with their later choice ofhand for delicate manipulations: it is the“dominant hand”, in human terms. We found asignificant sex difference in dominant hand
(Figure 1), with males tending to left- andfemales to right-hand dominance. Humans, ofcourse, show population right-handedness in both
sexes, normally explained by a species-specific“right-shift” gene （18, 19）. Comparing between
the sexes, the human pattern—women morestrongly lateralized than men—is exactly what
would be expected if the right-shift had beensuperimposed on a pre-human pattern of female
right- and male left-handedness. We suggest thatthe ancestral pattern has been retained inmodern chimpanzees, but is only brought out bychallenging bimanual manipulations such as
Saba eating, because as arboreal animals
chimpanzees are more generally rewarded forambidextrality （14）.
Plant food processing by great apes therefore
proves to be a useful site for meaningfulcomparison of cognitive skill in the great apes.
Past comparisons have been blighted by the
species-specific nature of the most compelling
evidence: chimpanzee social behaviour andtool-use, gorilla plant-processing, orangutan
locomotion and (in one population) tools.
Comparing on the ‘level playing field’ of plant
processing, we find that when chimpanzees deal
with complex manual problems they employ
elaborate, hierarchically-organized programs, as
is already known in gorillas. Like gorillas, they

Pan Africa News, 10(1), June, 2003

Figure 1. Sex differences in hand preference.
Distribution of Mahale chimpanzees, according to
the preferred hand for manipulative actions whenprocessing Saba and Citrus fruits. The X-axis
shows an individual’s degree of right-handprefernce; thus, 0 = completely left-handed, 50 =ambidextrous, 100 = completely right handed.
Males (15 individuals) are shown in black, females(24) in stipple.

show co-ordination both between the two hands
and among individual digits in different executiveroles, an obvious parallel with humans (20, 21).
The parallel is even tighter when theirsex-differentiated handedness in a bimanual task
is considered, with Mahale chimpanzees
presenting a possible model of the original
pattern of laterality of the last common ancestor
and explaining the sex differences in degree ofhandedness seen in humans today. However, it is
intriguing that in development of these
considerable manual skills, we find that mostontogenetic changes can be explained bymaturation and energy-optimization strategies ofthe mother, rather than advanced social learning
mechanisms. Within this more mundane picture
there is certainly scope for extensive incidentalsocial learning; but it is most likely that simple
processes, such as affordance learning and“unintentional” imitation by behaviour-parsing,
may underwrite much of the organizedcomplexity and impressive skills of great apes.

References(1) Byrne RW, Corp N, Byrne JME 2001. Estimating

Pan Africa News, 10(1), June, 2003
the complexity of animal behaviour: How
mountain gorillas eat thistles. Behaviour 138:525-557.
(2) Byrne RW, Corp N, Byrne JM 2001. Manual
dexterity in the gorilla: bimanual and digit roledifferentiation in a natural task. Animal Cognition
4: 347-361.
(3) Byrne RW, Russon AE 1998. Learning by
imitation: a hierarchical approach. Behav Brain
Sci 21: 667-721.
(4) Corp N, Byrne RW 2002. Leaf processing of wild
chimpanzees: Physically defended leaves reveal
complex manual skills. Ethology 108: 1-24.
(5) Corp N, Byrne RW 2002. The ontogeny of manual
skill in wild chimpanzees: Evidence from feedingon the fruit of Saba florida. Behaviour 139:
137-168.
(6) Bruner J 1970. The growth and structure of skill.
In Connolly KJ, (ed) Mechanisms of Motor Skill
Development, pp 63-94. Academic Press: NewYork.
(7) Wood D 1989. Social interaction as tutoring. In
Bornstein MH , Bruner JS, (eds) Interaction in
Human Development, pp 59-80. Lawrence
Erblaum Associates: Hillsdale, New Jersey.
(8) Tomasello M, Kruger AC, Ratner HH 1993.
Cultural learning. Behav Brain Sci 16: 495-552.
(9) Byrne RW 1999. Imitation without intentionality.
Using string parsing to copy the organization of
behaviour. Animal Cognition 2: 63-72.
(10) Byrne RW 2002. Imitation of complex novel
actions: what does the evidence from animals
mean? Advances in the Study of Behavior 31:
77-105.
(11) Boesch C 1991. Teaching among wild chimpanzees.
Anim Behav 41: 530-532.
(12) Custance DM, Whiten A, Bard KA 1994. The
developmentofgesturalimitationandself-recognition in chimpanzees (Pan troglodytes)
and children. In Roeder JJ, Thierry B, Anderson
JR, Herrenschmidt N, (eds) Current Primatology:

Vol. 2: Social Development, Learning and
Behaviour., pp 381-387. Université Louis Pasteur:
Strasbourg.
(13) Whiten A, Custance DM, Gomez J-C, Teixidor P,
Bard KA 1996. Imitative learning of artificial fruit
processing in children (Homo sapiens) andchimpanzees (Pan troglodytes). J Comp Psychol
110: 3-14.
(14) Corp N, Byrne RW 2003. Sex differences inchimpanzee handedness. Am J Phys Anthrop 121:in press.
(15) McGrew WC, Marchant LF 1996. On which side of
the apes? Ethological study of laterality of handuse. In McGrew WC, Marchant LF, Nishida T,(eds) Great Ape Societies, pp 255-272. Cambridge

7
University Press: Cambridge.
(16) McGrew WC, Marchant LF 1999. Laterality ofhand use pays off in foraging success for wild
chimpanzees. Primates 40: 509-513.
(17) Corballis MC 1991. The Lopsided Ape. Oxford:
Oxford University Press.
(18) Annett M 1985. Left, Right, Hand and Brain: The
Right Shift Theory. London: Lawrence Erlbaum.
(19) McManus IC 1985. Handedness, language
dominance and aphasia: a genetic model.
Psychological Medicine Monograph Supplement 8:
1-40.
(20) Fragaszy DM 1998. How non-human primates use
their hands. In Connolly KJ, (ed) The
Psychobiology of the Hand, pp 77-96. Mac Keith
Press: Cambridge.
(21) Boesch C, Boesch H 1990. Tool use and tool
making in wild chimpanzees. Folia Primatol 54:
86-99.

<NOTE>A Case of Infant Carrying by an
Adult Male Chimpanzee in the
Budongo Forest
H. Notman¹ and J. Munn²¹Department of Anthropology, University of Calgary.
²Department of Archaeology and Anthropology,
Australian National University.

Introduction
Observations of chimpanzee males kidnappingand killing conspecific infants are commonplace.
In many cases, infanticide is succeeded bycannibalism (1).
While not all kidnappings result in infanticideand cannibalism, observations of chimpanzee
males subsequently “caring” for stolen infants are
rare, although they have been reported in otherprimate species (2). Despite the coercive mannerin which infants might be attained, such
instances in which there is a shift in primary
caregiver from the mother to another older
individual have been loosely described as“adoptions” (3), or “transient adoptions” when theshift is temporary (4). Depending on the age ofthe infant being held by the male, the end
product of a kidnapping and adoption may
essentially equate to infanticide; i.e., unweaned
infants that are not returned to their mothers

8

Pan Africa News, 10(1), June, 2003

within a short period of time are likely to die fromstarvation or dehydration. The proximate causesof transient adoptions of infants by adult males
are unclear, although it has been proposed forsome species that infant carrying by males may
function as a “buffer” from aggression by othermales (5).

needed to be fully supported by JM’s arm. Thisappeared to hamper him considerably and he wasunable to keep up with other individuals in his
party. Despite the infant’s listlessness, it stillsquealed forcefully, though less often, when
moved. JM again bedded that night with theinfant still alive.

The following observation concerns the
temporary carrying and “care” of a newborn
infant by an adult male from the Sonso
community of the Budongo Forest, Uganda.

On December 15, JM was not found until latemorning. The infant appeared to be dead,although JM still carried it. No indications ofphysical injury were apparent on the infant. JM
poked at the infant periodically as it lay on his
chest, but otherwise ignored it. JM was not foundby observers in the afternoon, and was not seen
until the next day when he was no longer
carrying the infant. No fecal samples werecollected to determine if JM had consumed thedead infant.

Observations
Observations of this incident were made in
December 1999. On December 13 at 09:10,
Jambo (JM), a high-ranking adult male, wasspotted resting on the ground while holding a
newborn male infant. The infant’s eyes wereclosed, its body very small, and body hair sparse.
Several other chimpanzees were present andwere behaving in an excited manner, but no
particularfemalechimpanzee
appeared
distressed or anxious in a way that would
indicate she was the victim of an infantkidnapping.
The
infantwas
producinghigh-pitched squeals and whimpering, and JM
responded by “cuddling” the infant closer to hischest with his arms, although the infant was able
to grasp JM’s chest hair.
Throughout the day, JM carried the infant on
his chest, and occasionally supported it with hisarm by walking tripedally. During resting periods,
the infant tried to suckle JM. When JM wasmoving, the infant screamed intermittently,
suggesting it was experiencing pain or distress.
At 18:46, JM bedded down with the infant.
On December 14, JM left his bed at 06:25,
with the infant who was now clinging very
weakly with one arm, but still screaming
forcefully when moved. JM held the infant with
one arm near his crotch when he walked, andcarried it with his foot when climbing. No
individuals were showing any interest in JM or
the infant. JM paid little attention to the infant
other than to carry it, and to occasionally prod orlightly groom it when it lay on his chest. By
mid-afternoon the infant was totally listless andDiscussion
This report concerns the carrying and limited“care” of a newborn infant by a male chimpanzee
for at least two days, until just after the infant’s
death. JM was found with the infant wellwithin the community home range, and the
behaviour of the surrounding group members on
the morning of December 13th suggests theacquisition of the infant had occurred shortly
before our discovery of the group. Alternatively,
other chimpanzees may have just become awareof JM’s infant and were responding accordingly.
We therefore have no way of knowing whether
the infant was born to a female from within the
Sonso community.
The proximate motives for JM’s snatching andsubsequent carrying of the infant are also unclear.
It is possible that JM was initially motivated byinfanticide but then aborted his goal when hebecame fixated on the infant, perhaps evenenjoying the “attention” he received initially fromothers as a result. Reports of captive apes,
includingmales,
becoming
fixatedon“playthings” or “pets” are not uncommon (6, 7),
and it is possible that JM’s interest in the infant
was initiated by novelty but then waned once theinfant became listless and died. In any event,
this observation suggests that current proximate
explanations for kidnapping should include thePan Africa News, 10(1), June, 2003

9

possibility that males are motivated by interestin the infant as a “possession” or object of interest,and not solely as a source of meat or means tocreate a reproductive opportunity.
Research was financed by the NSERC of
Canada, The Calgary Zoo and the University ofCalgary to HN and by the Australian National
University to JM.
Thanks to K. Derbyshire for assistance inbackground research.

References(1) Hamai M, Nishida T, Takasaki H, Turner L 1992.
New records of within-group infanticide andcannibalism in wild chimpanzees. Primates, 33:
151-162.
(2) Collins DA, Busse CD, Goodall J 1984.
Infanticide in two populations of savanna baboons.
In: Infanticide: Comparative and Evolutionary
Perspectives. G. Hausfater and S.B. Hrdy (eds),
New York: Aldine Publishing.
(3) Thierry B, Anderson JR 1986. Adoption inanthropoid primates. International Journal ofPrimatology, 7: 191-216.
(4) Thierry B, Herrenschmidt N 1985. A case of“transient adoption” in a captive group of Tonkean
macaques (Macaca tonkeana).
Lab. Prim.
Newsletter, 24:1-3.
(5) Strum SC 1984. Why males use infants. In:
Primate Paternalism, D.M. Taud (ed). Van
Nostrand Reinhold: New York.
(6) Patterson F, Linden E 1981. The Education of
Koko. Holt, Rinehart and Winston: New York.
(7) Debby Cox, personal communication. EntebbeWildlife Education Center.

<NOTE>
Eleven-Year Old Male
Chimpanzee Outranks
Ex-Alpha Adult Male at Bossou
Michio Nakamura (Japan Monkey Centre) and
Gaku Ohashi (Kyoto University)

Introduction
Dominance

among

chimpanzees(Pan

troglodytes) is usually measured by thepant-grunting vocalization directed from thesubordinate to the dominant (1, 2). Although alinear dominance hierarchy exists among most
adult males, some dyadic relationships areambiguous (1, 3). In contrast, there is adistinctive social gap between adult males andadolescent males, i.e. all adolescents pant-grunt
to all adults (4). Adolescence in male chimpanzees
is thus a period between sexual maturity andsocial maturity which is achieved at about 15
years of age (5, 6, 7 but see 8). We report here thecase of YL, a young male at Bossou, whooutranked an old ex-alpha adult male TA andbecame the beta male at the age of 11 years, and
who also showed insubordination to the alphamale FF.

Methods
Wild chimpanzees have been continuously
studied at Bossou, Guinea since 1976. In morethan two decades, there has been little change in
the group size (8), which is currently 19 including
two adult males. Ohashi followed FF for 1210
hours from Jul. 2002 to Mar. 2003, andNakamura followed 9 individuals including all
four of the sexually mature males (Table 1) for
241 hours from Jan. to Mar. 2003. Observations
were made during focal follows that included
non-focal individuals around the target subjects.

Observations
YL (Figure 1) pant-grunted to TA until at leastJan. 2003, but no pant-grunts were heard after
that. YL was completely subordinate to FF until
early
Feb.
2003,
showing
exaggerated
pant-grunts characteristics of adolescent males.
On 8th Feb. 2003, TA showed sexual
possessiveness to an estrous female Fn in theparty that included YL, PO and some others. PO
copulated stealthily with Fn, which caused great
uproar in the party, and YL and TA displayed ateach other. Neither pant-grunted, but finally TA
grimaced, screamed, and sought assurance fromYL. After that, TA groomed first with YL’s
mother Yo who had rushed to the uproar, andthen with YL for about 30 minutes.
In the next evening, while TA and YL ate
Rhaphiostylis beninensis fruits with six other10

Pan Africa News, 10(1), June, 2003

chimpanzees,
TA
Table 1 Four Mature Males at Bossou.
began
to
make
Name (Abbr.)
Year of BirthAge in 2003 Mar.
Motheropportunistic
Tua (TA )unknown (adult in 1976)
old
unknown
displays around Fn.
When Fn screamed,
Foaf (FF )1980 late23
Fana (alive)
YL also began to
Yolo (YL )1991 middle
11
Yo (alive)
display and when YL
Poni (PO )1993 Feb.
10
Pama (alive)
approached TA, hepant-grunted to YL.
we could not follow further developments.
On 18th Feb. 2003, TA and PO ranged awayfrom others. When they reunited with YL that
Discussion
evening, TA pant-grunted without YL displaying
Eleven years old is a very young age to outrank
or showing aggression.
any adult males and to show insubordination to
As FF was ranging far to the north in
the alpha male. We propose four mutuallyconsortship with a female from 8th to 21st Feb, it
non-exclusive explanations for this.
is possible that TA’s submissive behavior to YL
was temporary, because of the absence of support(1) Demography: With only a few mature males,from FF. However, on 2nd Mar., TA pant-grunted
it may be difficult for older males to maintainto YL when FF was in the nearby tree, so it was
status higher than their actual physicalobvious that YL dominated TA and was now thestrength by using coalitions or alliances, withbeta male.
other males.
After FF’s return, YL never pant-grunted to FF(2) Mother’s proximity: YL’s mother, Yo, had no
except for once on 22nd Feb. YL tended to walkchildren younger than YL, and she often
away from FF, but when he met FF hefollowed and stayed near YL. She sometimes
sometimes displayed from a distance of 10-20m
engaged in fights with males, so herstanding bipedal and swaying his arms with hairproximity may have indirectly helped YL toerection. For a while, FF made no aggression
raise rank.
against YL’s insubordination except for(3) Early physical growth: It is possible that
displaying back, but on 12th Mar., FF beat YL
nutrition is better in Bossou than otherout of the tree of Ficus umbellata. Unfortunately,places, because of the cultigens in their diet.
this was the last day of our research at Bossou, so

Figure 1. Eleven-year old male Yolo (YL)Pan Africa News, 10(1), June, 2003
YL looked much bigger than typical 11
year-old males and almost equaled adults at
Mahale. Sugiyama (8) treated 12 years asadult at Bossou instead of the usual 16 years.
Also, females at Bossou have their first birthmore than three years younger than females
in other wild populations (9). These also
imply that physical growth is generally
earlier in Bossou. This is not the difference
betweensubspecies,
becauseTaï
chimpanzees (same subspecies as Bossou) do
not seem to have this earlier growth (7).
(4) TA’s old age: TA was prime adult in 1976 (8),which made him at least 45 years old in 2003.
It is possible that he was forced by aging togive way to the young.
This report implies that chimpanzee males
have the potential to rise in rank earlier thanusual, under some conditions such as early
physical growth and few social constraints.
However, large body size is not enough to attainhigher rank, as one male in Mahale, Bembe, hadbeen low-ranking although he was large-bodied.
If there are many adult males in the group, older
males may skillfully exploit the histories ofrelationships with other adults to maintainhigher social status than the physically developed
but young males.

References(1) Bygott JD 1979. Agonistic behavior, dominance,and social structure in wild chimpanzees of Gombe
National Park. In: The Great Apes, Hamburg DA,
McCown ER (eds), Benjamin/Cummings, Menlo
Park, pp: 405-427.
(2) de Waal FBM 1982. Chimpanzee Politics. The
Johns Hopkins University Press, Baltimore.
(3) Nishida T, Hosaka K 1996. Coalition strategies
among adult male chimpanzees of the Mahale
Mountains, Tanzania. In: Great Ape Societies,
McGrew WC, Marchant LF, Nishida T (eds),
Cambridge
University
Press,
Cambridge,
pp.114-134.
(4) Hayaki H, Huffman MA, Nishida T 1989.
Dominance among male chimpanzees in the
Mahale Mountains National Park, Tanzania: apreliminary study. Primates 30:187-197.
(5) Goodall J 1983. Population dynamics during a 15
year period in one community of free-living
chimpanzees in the Gombe National Park,
Tanzania. Z Tierpsychol 61:1-60.

11(6) Hiraiwa-Hasegawa M, Hasegawa T, Nishida T
1984. Demographic study of a large-sized
unit-group of chimpanzees in the Mahale
Mountains, Tanzania: a preliminary report.
Primates 25:401-413.
(7) Boesch C, Boesch-Achermann H 2000. The
Chimpanzees of the Taï Forest. Oxford University
Press, Oxford.
(8) Sugiyama Y 1999. Socioecological factors of malechimpanzee migration at Bossou, Guinea.
Primates 40:61-68.
(9) Fujita S 2003. Reproductive Biology in Wild

Female Primates: Variety in Hormonal Profiles,
Behavior and Reproductive Parameters. Ph.D.
Dissertation, Kyoto University, Inuyama.

<NOTE>A Note on the Southern
Neighboring Groups of M groupin the Mahale Mountains
National Park
Masaki Shimada

Graduate School of Science, Kyoto University, Kyoto,
Japan

Introduction
The M group is a well-habituated group of
chimpanzees in Mahale that has become themain target of research and eco-tourism. In
addition, the M group has several neighboringgroups (1).
Two of these neighboring groups to the south of
the M group’s range are called the N and L
groups (1, 2). The range of the N group has been
estimated to extend from lakeside to Mt.
Mkulume and Mt. Mhela, and that of the L groupextends over the Lubugwe, Msuma and Ntala
Valleys. Because there has been no more
information on those groups since the 1980s, it isdifficult to estimate where and in which patternthey are ranging today.
It is important to immediately investigate theranging areas and patterns of these neighboringgroups. This would serve not only to understandthe between-group relationships but also to12

Pan Africa News, 10(1), June, 2003

Table 1. Direct Encounter with Chimpanzees
obs. timemembership (*)

party
size

3/21 Msoffwe V.

N

10:03-10:44

AM*2,
YF(estrous)*
1

3

feed/bark/odoratissima
attack(seeds)

3/25 Syankuhe V.

L

16:09-16:41

AM*2, A?*1

3

feed

3/25 Syankuhe V.

L

17:03-17:08

AF*1, YM*1

2

rest

place

group
activity

what they arefeeding

estimated
unit groupdateobs. from

Dioscorea

groundboat/
Pterocarpus
tinctorius (leaves) groundboat

Pterocarpus
boattinctorius (leaves)Pterocarpus
tinctorius (leaves),
AF*3, YF*1,
feed/travelboat
3/26 Nkwasi V.
L
10:07-10:50
8
Diplorhynchus
Y?*4/ play/rest
condylocarpon(seeds)
3/26 Syankuhe V.
L
11:30-11:33
AF*1, Y?*1
2 rest/groom
boat* Each symbol represents as follows, A: adult, Y: young, juvenile, infant, M: male, F: female
3/25 Syankuhe V.

L

17:16-17:22

AF*1, YF*1

2

feed/rest

Table 2. New Evidences of Chimpanzees
estimated
type of evidence
unit group
3/21 Msoffwe V.
N
trodden path
3/23 Ilanga V.
N
bed*3
3/23 Ilanga V.
N
trodden path
3/23 Ilanga V.
Nremenant of bark fragments
3/25 Lubugwe V.
Lremnant of leaves
3/26 Lufungu V.
L
bed*3
3/26 Mufuga V.
L
bed*2
3/26 between Syankuhe and LufunguL
bed*4
3/26 between Syankuhe and LufunguLremnants of seed pods
date

place

provide basic information to use in habituatingthese chimpanzees for tourism and conservationin the future.

Surveying Area and Methods
A survey was conducted by three assistants
and myself in the rainy season from March 20 to
27, 2002. The survey area extended from theIlanga Valley at the north end to the Siyeswe
Valley at the south end. We drove a small boat
slowly about 50 m away from the shore along thecoast at least once and counted all of the beds insight. The length of this area from north to south
is about 15 km.
We also trekked inland less than 2.5 km fromthe lakeside at Mt. Mkulume, Msoffwe Valley,
Lubugwe River and the slope between Syankuhe
and Lufungu Valleys. The area is mostly a steep

species of remnants

Brachystegia bussei
Ficus exasperata

Diplorhynchus condylocarpon

slope covered with the Miombo woodland, whichstarts directly from the lake except for theriverine forest in some restricted areas along thevalleys (2).
Whenever we encountered chimpanzees, werecorded them with a digital video camera. We
also recorded information on their beds, trodden
paths, and eaten food items. New evidence(0–1day old) was used to estimate the movementof chimpanzee parties and old evidence (morethan 2 days old) to estimate the range of each
unit group.
Data on the M group during the survey was
kept by the rest of the research staff.

Distribution of N and L groups
We found 131 chimpanzee beds mostly along
the lakeside area. However, we found no beds

Pan Africa News, 10(1), June, 2003

13

M group

Lubulungu R.

N
3/23

Lake Tanganyika

Ilanga V.
BB
B

B

B

B

3/24

Mm

Mt. Mkulume3/22(10+)
Kanamsoffwe V.

3/21

3/21(3)

MusoffweV.

N group

3/22(10+)
B

3/21

B

Mt. Mhela

Karambo V.

B
Ntala V.

B
B
BB

2 km

B

B

B
B

Nkwasi V.

3/26(8)3/25(3)3/25(2)B

L group

3/27
B
BB

Syankuhe V.
BB

B B
B
B

Direct encounter3/25(2)
Vocal encounter3/26(2)B
Chimpanzees' bed(s)3/26(8) Date of obs. and the party
size
Fig. 1 Map of the Surveying Area

Msuma R.

Lubugwe R.

B

Lufungu V.

B

B
B
B
B
B

Mufuga V.

B
B

B
Siyeswe V.

14
between Kanamsoffwe and Karambo Valleys(width=3 km), though the distribution of beds inthe other area was continuous (Fig. 1). The
vegetation and topography in this area are notdiscontinuous. Thus, this does not contradict the
1980s’ estimation of the ranging areas of the N
and L groups (1).

Ranging patterns and other features
Through the survey period, many types ofsmall parties of both N and L groups wereranging separately from each other (Table 1).
Direct and vocal encounter with the N groupfrom March 21 to 24 (Fig. 1) shows a good
example of their fission-fusion society in the laterainy season: Two parties, each including about
10 individuals (or more), and a party including
two adult males and an estrous female separated
on March 21, and then the two bigger parties
chorused to each other on March 22. Although we
did not observe them on March 23, the twoparties seemed to join together and move to thenorth of the Msoffwe Valley on March 24. In
addition, at least one other party existed in thenorth region of the Ilanga Valley on March 23,
and they may have ranged independently. The
estimated movements of the N group parties areshown in Fig. 1.
As for the M group’s ranging during the survey,
a staff member directly observed a motherchimpanzee and her son only once on March 23 in
the southern part of the M group’s range.
The observed food items of the L group weremainly leaves of Pterocarpus tinctorius and seedsof Diplorhynchus condylocarpon (Tables 1, 2).
These are common varieties of woodlandvegetation (2). Since such food is also used by the
M group chimpanzees in the rainy season(Shimada, personal observation), it is likely that
the L group chimpanzees normally use thelakeside area covered with the woodland in thesame part of the year.
These data suggest that it is a common
phenomenon for all three unit groups to spreadout widely in many small parties during therainy season.

Reaction to humans

Pan Africa News, 10(1), June, 2003
When we approached a party in the range of
the N group on March 21, one of the males
escaped silently as soon as he discovered us, andthe others continued barking “Wraa” to us. On
the other hand, as long as we observed from theboat, no chimpanzee of the L group seemed to be
especially nervous about human observers. WhenI tried to land and approach three adults on
March 25, one of the males hesitated to leave thefeeding tree and looked at me for a few minutes.
These observations gave us the impression that
the L group chimpanzees were more habituatedthan the N group chimpanzees. The highfrequency L group chimpanzees use a lakesidearea in the late rainy season while humans passby this area in boats. Consequently, we canassume that this situation facilitates more
frequent encounters between chimpanzees andhumans and, as a result, has already advanced
the habituation process to some extent.
The study was supported by funds from MEXT
Grants-in-Aid for Scientific Research (Basic
Research A1, #12375003 to T. Nishida) and forthe 21 Century COE Research (#A2 to T.
Nishida).

References(1)

Nishida T (ed.) 1990. The Chimpanzees of the(2)

Mahale Mountains: Sexual and Life History
Strategies. University of Tokyo Press, Tokyo.
Anonymous 1980. Study for the Proposed Mahale
Mountains National Park: Final Report. Japan
International Cooperation Agency, Tokyo.

<NOTE>
Evidence for Leaf Swallowing
Behavior by Savanna
Chimpanzees in Senegal- a New
Site Record
Jill D. Pruetz¹ & Susannah Johnson-Fulton²¹Department of Anthropology, Iowa State University,
Ames, IA 50011²New Mexico State University, Las Cruces, NM 88003

Pan Africa News, 10(1), June, 2003
Evidence of leaf swallowing, a proposed form of
medicinal plant use by savanna chimpanzees wasrecently recorded at the Fongoli study site insoutheastern Senegal. Since April 2001, theFongoli community of chimpanzees has beenstudied in an effort to better understand theecology of chimpanzees in an arid environment.
The habitat can be described as a mosaic ofwoodland and savanna containing areas ofbamboo forest and grassland and interspersedwith isolated areas of gallery forest (<1% of studyarea) and larger areas of laterite plateau.
Chimpanzees at this site have been estimated tooccur at a density of 0.09 individuals per km² (1).
The site lies approximately 40 km E of the Parc
National du Niokolo Koba and 10 km NW of thetown of Kedougou, in southeastern Senegal.
Field assistants monitor chimpanzee ranging,
diet, and habitat use within an approximately
50km² study area. Data are collected on
chimpanzee beds as well as observations ofchimpanzees. Habituation of this chimpanzee
community is in progress, and diet data are basedon analyses from fresh fecal samples. Currently 5
individual chimpanzees have been identified, butopportunities for behavioral observations arelimited. However, research assistants have beenable to remain with chimpanzee parties for up to
9 hours when they are attracted to dry season
water sources. The rainy season begins in
June-July, while the extensive dry season begins
in November-December.
Chimpanzees share their range with baboons(Papio hamadryas papio), green monkeys(Cercopithecus sabeus), and patas monkeys(Erythrocebus patas). People of the Malinke,
Bassari, Bedik, and Diahanke groups also share
this area with the chimpanzees and do not huntthem. Much of the large mammalian fauna has
been eliminated from the area, but ungulates
such as warthog and bushbuck remain at low
densities.
Since April 2001, over 400 fecal samples havebeen analyzed to determine the dietary habits of
Fongoli chimpanzees. In addition to recording
the number of seeds and their plant species
within feces, data are also collected on thepercent fiber contained per fecal sample andother characteristics, such as the presence of

15
insect and vertebrate parts and leafy vegetation.
Eighteen samples have been identified asindicative of leaf swallowing behavior.
Fecal samples thought to be indicative of leaf
swallowing were observed to contain a large
amount of undigested and unchewed leaves withsome leaf fragments also included. Five samples
were collected during the late rainy season that
contained these unchewed leaves:
27 September 2002
10 whole leaves
3 October 2002
>10 whole leaves
22 October 2002
>50 whole leaves + 2
large grass leaves
22 October 2002
>10 whole leaves + 1
large grass leaf
22 October 2002
4 whole leaves.
The plant these leaves originated from was foundafter two weeks of searching and comparing in
the field. Samples were then compared under amicroscope and they are believed to be identical.
This herbaceous plant is from the legume family(Fabaceae). The leaves are between 3-6 cm longand 4-5 mm wide with a slightly rounded baseand an apex that is mucronate or tipped with asharp, abrupt point. The pubescence of theupper and lower surfaces of the leaves is strigose,
which means bearing straight, stiff, sharp,
appressed hairs.
Several fecal samples also indicated that
Fongoli chimpanzees swallow whole large
amounts of grass leaves belonging to the species
Andropogon chevalieri Reznik. During the
beginning of the rainy season, on July 22, 2002, a
fecal sample was collected that was made up
almost entirely of wadded grass leaves. Overtwo months later, near the end of the rainyseason, on Sept. 27, Oct. 25, and on Nov. 14, more
samples were found that also contained large
amounts of unchewed grass leaves. The grass leaf
sections were up to 25 cm long and around 1 cm
wide. The leaf surfaces are scabrous (rough) andthe leaf margins are fringed with short hairs.
Three other samples were collected that
contained small amounts of unchewed grassleaves (between 1 and 2 leaves present per
sample). Similarly, on June 18 and 19, 2003 twofecal samples were observed to contain >5 entire

16
grass leaves measuring over 10 cm in length and
4 mm in width that may also belong to the same
species.
On 31 December 2002, during the early part ofthe dry season, 18 entire or mostly entire leaf
fragments were found contained in one fecal
sample collected within a small strip of gallery
forest. Leaves and leaf fragments averaged 56.9mm in length (range: 40-102 mm) and 19.8 mm
in width (range: 13-27 mm) (N=18). A numberof smaller leaf fragments were also found in thedung sample. Leaves were folded/wadded whensieved from the fecal sample, but no evidence ofchewing or any digestion was evident on theleaves.
Leaves were identified as Ficus
asperifolia after comparison with a series ofplants in the study area. Less than 30 m from
where the fecal sample was collected, a recent
ground bed made from two F. asperifolia saplings
was recorded.
This particular plant ischaracterized by very coarse leaf surfaces. Six
other instances of whole leaf swallowing wereobserved at Fongoli (between 1 and 2 leaves per
sample). These leaves were different than the F.
asperifolia, legume, and grass leaves. Similarly,
the surfaces of some of the leaves were rough.
A study of parasite loads of Fongoli
chimpanzees as well as future studies of feeding
behavior here will provide a test of the hypothesisthat Fongoli chimpanzees use plants medicinally.
We hypothesize that Fongoli chimpanzees
swallow whole leaves in a manner conducive totheir medicinal use as reported for plants such as
Aspilia and F. exasperata in the Kibale Forest,
Uganda and at other sites (2). Chimpanzees fold
and ingest physically irritating leaves whole, andanalyses suggest such behavior helps to eliminate
gut parasites (3). Chimpanzee fecal samples had
not yet been collected for analyses of parasiteload, save for the June 2003 samples. Adult
parasites have been observed in at least 3
different fecal samples.
Given the aridity of the study site and thesignificant differences between the vegetation
here and that characterizing other sites wherechimpanzees have been assumed to use plants
medicinally, this report of possible medicinal
plant use has important implications for theuniversality of this aspect of chimpanzee
behavior and ecology and, perhaps, cultural

Pan Africa News, 10(1), June, 2003
implications as well.
Thanks to the Republic of Senegal, theDirection des Parcs Nationaux, Departement desEaux et Forets, Bill McGrew, Peter Stirling,
Clayton Clement, Philip Fulton, Tom LaDuke,
Dondo Kante, Mboule Camara, Kaly Camara,and the people of Fongoli, Petit Oubaji, andDjendji for their assistance in the project.

References
(1)

(2)
(3)

Pruetz JD, Marchant LF, Arno J, McGrew WC
2002. Survey of savanna chimpanzees (Pantroglodytes verus) in southeastern Senegal. Am J
Primatol 58: 35-43.
Huffman MA 1997. Current evidence forself-medication in primates: a multidisciplinary
perspective. Yb Phys Anthrop 40: 171-200.
Huffman MA, Caton JM 2001. Self-induced
increase of gut motility and the control of parasitic
infections in wild chimpanzees. Int J Primatol 22:329-346.

Pan Africa News, Vol. 10, No.1
Published in June, 2003
Address:
Editorial Office, Pan Africa News
Department of Zoology
Graduate School of Science
Kyoto University
Sakyo, Kyoto 606-8502
JAPAN
TEL: (+81)75-753-4085
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E-mail: PAN@jinrui.zool.kyoto-u.ac.jp