Pan Africa News

Vol. 13 , No.1

JUNE, 2006
P. A. N. EDITORIAL STAFF

CONTENTS:

Chief Editor:
Toshisada Nishida, Japan Monkey Centre, Japan
Associate Editors:
Christophe Boesch, Max-Planck Institute, Germany
Jane Goodall, Jane Goodall Institute, USA<NOTE>New evidence of honey-stick use bychimpanzees in Southeast Cameroon.
Deblauwe Isra

2

Takayoshi Kano, Kyoto University, Japan
Tetsuro Matsuzawa, Kyoto University, Japan
William C. McGrew, University of Cambridge, UKJohn C. Mitani, University of Michigan, USA
Vernon Reynolds, Budongo Forest Project, UK
Yukimaru Sugiyama, Kyoto University, Japan
Richard W. Wrangham, Harvard University, USA<NOTE>
Pan paniscus, sometimes a linguistic issue.
Jacky Maniacky

4<NOTE>
Grooming hand clasp by bonobos of Lui

Editorial Secretaries:
Noriko Itoh, Kyoto University, Japan
Koichiro Zamma, Kyoto University, Japan
Michio Nakamura, Kyoto University, Japan
Instructions to Authors:
Pan Africa News publishes articles, notes, reviews, forums,
news, essays, book reviews, letters to editor, and classified

Kotal, Democratic Republic of Congo.
B. I. Fruth, G. Hohmann, M .M. Beuerlein and
W. C. McGrew

6<NOTE>
A louse egg left on a leaf.
Koichiro Zamma

8

ads on any aspect of conservation and research regarding
chimpanzees (Pan troglodytes) and bilias (P. paniscus). Contributors are requested to write in English and the papers
except forums, reviews and essays should usually be 1,500
words or less. Manuscripts should be submitted by e-mail to:

pan_ed@jinrui.zool.kyoto-u.ac.jp
Photos and figures, however, should be sent by air mailto: T. Nishida, Department of Zoology, Graduate School of
Science, Kyoto University, Kitashirakawa Oiwakechou, Sakyo,
Kyoto, 606-8502, Japan.
Publication of the next issue will be December 2006.
Deadline for manuscripts is the end of November.

<NOTE>
Bossou chimpanzees crossed the national
border of Guinea into Liberia.
Gaku Ohashi

102

Pan Africa News, 13(1), June, 2006

<NOTE>New Evidence of HoneyStick Use by Chimpanzees inSoutheast Cameroon.
Deblauwe Isra
1. Centre for Research and Conservation (CRC),
Royal Zoological Society of Antwerp (RZSA)
2. University of Antwerp (UA), Department of Biology

is officially unprotected and situated in thesouthwest corner of the logging concession
10 047 of the Fip.cam company. Secondary
forest covers more than half of the area. The
density of chimpanzees is conservatively
estimated at 0.9 individuals/km² 9. They are
not habituated to human observers. Indirect
data were collected during chimpanzee
tracking and other activities from April to July
2002, May to August 2003 and September
2004 to April 2005.

INTRODUCTION

The use of sticks to obtain honey bychimpanzees is widely known1, 2, 3, 4, 5, 6, 7, 8. Botharboreal and underground nests of stinging(Apis sp.) and stingless bees (Meliponini) are
opened to extract the honey, often together withlarvae, pupae and adult bees. Chimpanzees
can dig for honey with their hands3, but often
use one tool4, 7, 8 or a tool-set2, 5, 6. This tool
behaviour varies across sites and within sites
across bee species 4, 5, 7, 8. It is important tocontinue recording tool-use at new sites, as it
will enlarge our knowledge about different tooltechnologies and cultural variations among
chimpanzee populations8.
The present study reports the first evidenceof stick use to obtain honey at the northern
periphery of the Dja Biosphere Reserve (DBR)
in Southeast Cameroon.
STUDY SITE AND METHODS

The study site (“La Belgique”) in Southeast
Cameroon, at the northern periphery of the
DBR (13,11°-13,17° E and 3,37°-3,45° N)

RESULTSTw i c e ( A p r i l 2 0 0 2 a n d J u n e 2 0 0 3 )evidence of chimpanzees digging for honeyof stingless bees (Meliponini) was foundalong chimpanzee traces (footprints) in the
study site, next to which no tools were found.
Probably chimpanzees dug for honey with theirhands. Pieces of the bee nest, with honey andchimpanzee hair sticking on them, were lying
next to the holes. Both traces were less than
one week old.
Four times (December 2004 (2 sticks),
February 2005 (2 sticks), April 2005 (5 sticks)
and April 2005 (4 sticks)) honey digging sticks
were collected at holes in the ground during
chimpanzee tracking (Tab. 1). In total 13
sticks were found next to (12 sticks) or still
fixed in (1 stick) four underground bee nests.
The sticks were less than one week old. They
were straight and sturdy and sometimes bothstick ends were used. The plant species usedas materials were: Oxyanthus spp. (23%, O.
unilocularis and O. speciosus ), Rinorea sp.

Tab. 1. Measurements of the holes, sticks, remaining stalks and discarded top
pieces of the honey digging traces (mean ± standard deviations, number andrange between brackets).

Pan Africa News, 13(1), June, 2006(15%), Maesobotrya klaineana (15%), Alchornea
floribunda (8%) and unknown species (39%).
Seven sticks (54%) had one (5 sticks) or two(2 sticks) brushes. The remaining stalks and/or
discarded top pieces of 11 sticks were foundback (Table 1). At two sites also a bigger stick
was found next to the hole with on one sideclumped soil, which seemed to be caused by
digging. One stick was very long (2.3 m long
and about 4 – 5 cm of diameter) and had aside branch starting in the middle. It was theremaining piece of a small tree (Maesobotrya
klaineana), cut a long time ago by a tracker
with a machete (this honey digging site wasfound on one of our transects). According to
the trackers the chimpanzees used the sharp
end of this cut stem to make or enlarge the holein the ground. The other big stick was also
more than 1 m long and about 4 cm in diameterand seemed to be used by the chimpanzees,
though the trackers were not sure of this.
Of 138 faecal samples analysed(methodology see 10), only four (3%)
contained heads of Meliponini bees. The
abundance score was rare (3 faecal samples) or
few (1 faecal sample).
DISCUSSION

No evidence was found of feeding on
honey of Apis sp. or stingless bees in trees,
which chimpanzees do at most other sites 4,
5, 6, 7, 8
. Chimpanzees in the periphery of the
DBR only seem to use tools to dig for honeyfrom stingless bee nests underground. Still,
Apis mellifera is present at our study site (pers.
obs.). First, the raiding of bee hives in trees
could have been overlooked as chimpanzees
are not habituated and could not be followed
continuously, and the tools might have beenleft in the tree, which is easy to miss. Second,
chimpanzees may take honeycomb pieces fromundisturbed beehives in trees with their hands3,
what does not leave many traces. Third,
the few heads of stingless bees found in the
faecal samples were not identified to genus or
species and might be from species nesting intrees. Still, the lack of Apis heads in the faecal
samples suggests that chimpanzees do not eat
honey from Apis hives in trees.

3

The honey digging sticks found in thisstudy are similar to sticks found in Gabon 5
and Uganda (Bwindi) 7 to get honey from
Meliponula and/or Apis hives in trees, and to
those found in Central African Republic (CAR)8
to get honey from stingless bees underground.
At other sites, tools used to dig for honey ofstingless bees underground are much shorter1, 4.
The difference in tool characteristics forunderground beehives between the sites isinteresting in terms of cultural variation.
Since not all long brush ends were used,
they did not seem to be manufactured by the
chimpanzees. Still, at all four sites at least
one brush end was inserted in the hole, next tocompacted ends. Therefore, we cannot exclude
the possibility that brush ends might have a
special function to absorb honey5.
The two big sticks found next to the smaller
sticks at two honey digging sites are longer but
similar in diameter to the stout chisels foundin Congo6 and the large tools from CAR and
Congo4. Since they were found together withthe smaller sticks and were as old, it could
be that chimpanzees used them as a toolset (in the same bout in sequence) to obtainhoney. This, together with the possible special
function of the brush sticks, would represent
the first tool-set (of two or three tools) to
dig for honey from underground bee nests.
However, more evidence needs to be collected
to be able to speak of 1) cultural variation inbee species eaten and in tool-use, and 2) honeytool-set use by chimpanzees at the periphery of
the DBR. Still, this small contribution to theavailable data on honey extraction shows how
widespread and complex this behaviour can be.
ACKNOWLEDGMENTS

The author thanks the RZSA, Durell
Wildlife Conservation Fund, the logging
company FIP.CAM, MINRESI (Ministère dela Recherche Scientifique et de l’Innovation,
Cameroon), MINFoF (Ministère de Forêt etde la Faune, Cameroon) and the 'Service deConservation de la Reserve de Faune du Dja'
for supporting this project. Fieldwork was
funded by the L.S.B. Leakey Foundation, theKing Leopold III fund for Nature Exploration

4and Conservation (RBINS), the Flemish InterUniversity Council (VLIR), the Father Louis
Bruyns Foundation (UA) and the Fund to
Promote Scientific Research in Africa (NBG,
Meisse). The first author was supported by agrant (BOF) from the UA and the RZSA andthanks the Flemish Government for structural
support to the CRC of the RZSA.
REFERENCES
1 . Ya m a g i w a J , Yu m o t o T, N d u n d a M ,Maruhashi T. 1988. Evidence of tool-use bychimpanzees (Pan troglodytes schweinfurthii)
for digging out a bee-nest in the Kahuzi-Biega
National Park, Zaïre. Primates 29:405-411.
2. Brewer SM, McGrew WC. 1990. Chimpanzee
use of a tool set to get honey. Folia Primatol
54:100-104.
3. Boesch C, Boesch H. 1990. Tool use and tool
making in wild chimpanzees. Folia Primatol
54:86-99.
4. Fay JM, Carroll RW. 1994. Chimpanzee tool
use for honey and termite extraction in Central
Africa. Am J Primatol 34:309-317.
5. Tutin CEG, Ham R, Wrogemann D. 1995.
Tool-use by chimpanzees (Pan t. troglodytes)
in the Lopé Reserve, Gabon. Primates
36:181-192.
6. Bermejo M, Illera G. 1999. Tool-set for
termite fishing and honey extraction by wild
chimpanzees in the Lossi Forest, Congo.
Primates 40:619-627.
7. Stanford CB, Gambaneza C, Nkurunungi
JB, Goldsmith ML. 2000. Chimpanzees in
Bwindi-Impenetrable National Park, Uganda,
use different tools to obtain different types ofhoney. Primates 41:337-341.
8. Hicks TC, Fouts RS, Fouts DH. 2005.
Chimpanzee (Pan troglodytes troglodytes)
tool use in the Ngotto Forest, Central African
Republic. Am J Primatol 65:221-237.
9. Guislain P, Dupain J. 2005. Sudden great ape
die-off in the periphery of the Dja Biosphere
Reserve. Gorilla Journal 30:28-30.
10. Deblauwe I, Guislain P, Dupain J, Van
Elsacker L. In press. Use of a tool-set by Pan
troglodytes troglodytes to obtain termites(Macrotermes) in the periphery of the Dja
Biosphere Reserve, Southeast Cameroon. Am J
Primatol.

Pan Africa News, 13(1), June, 2006

<NOTE>
Pan paniscus, Sometimes a
Linguistic Issue.
Jacky Maniacky
Linguistics Service
Royal Museum for Central Africa, Tervuren, Belgium

The question of how to name Pan paniscus
is not new. It is indeed the subject of an article
in PAN1, which reminds us how inappropriate
the term of "bonobo" is when compared tothose used by people living in the areas where
Pan panicus is found. It also concerns thepotential consequences such an incoherence
can have on scientific research and on projects
to protect the species. With this article, I
intend to support the term of "elya" from apure linguistic point of view.
Locutions such as the debated "dwarf/
pygmy chimpanzee" or "gracile chimpanzee"
are used to name Pan paniscus other than bya strict, scientific denomination. However,
nowadays the most common term isundoubtedly "bonobo", suggested by Tratz& Heck 2: they wrongly claimed it to be an"indigenous" name. This term is now said
to originate from a misspelling of "Bolobo"3,
a village on the bank of Congo river in the
Bandundu region (DRC). The first specimens
sent to Europe were reportedly found there. In
Tiene (Fig. 1), the language spoken in Bolobo,"elya" is the word for chimpanzee4. This term,
and related ones, are also found in Bolia 5,
Ntomba 6 and other languages of the Mongovariety7.
In Africa in general, and DRC in particular,
there is a large diversity of languages.
However, Pan paniscus can only be found ina few places. Consequently, the expected
number of languages which have a specificword for Pan paniscus is also limited. The
available data is not always mentioned
specifically with the meaning 'Pan paniscus' but
most frequently 'chimpanzee'. Nevertheless,
it appears from a comparative analysis that
there is an obvious correlation between
the localisation of the languages using the"elya" form and the distribution map of Pan

Pan Africa News, 13(1), June, 2006

Fig. 1 Some ethnic groups of DRC

paniscus. The link between "elya"-type and"Pan paniscus" is also reported in a fieldwork
note8. I would not forget that another term,"mokomboso"-type, is found to designate"chimpanzee" in that area: in Lingala 9 ,Buma10, Ngombe11 (Fig. 1), etc... In Mongo7(Fig. 1), it is clearly indicated as a borrowed
word. Finally, Tetela12 (Fig. 1) has words for'chimpanzee' completely different from thetwo main types mentioned above. All theseprove that when necessary, there is a linguistic
difference between Pan troglodytes and Pan
paniscus. Such an observation relativizes thevalue of the word "discovery", which scientists

5

have abused when designating
African realities.
Some remarks have to be madeabout the use of the word "elya" forPan paniscus. First, the spelling:"y" is voluntarily used instead of"i" to avoid "diaeresis" as saidin linguistics. In other words,
there is a distinct pronunciationof vowels "i" and "a"; thus on two
syllables, almost the way it would
be if the word were "eliya". For
what concerns number (singular/ plural), the whole languages of
the target area belong to the Bantu
linguistic group. The plural isdone by modifying the prefix (thebeginning of a word) accordingly.
Thus for "elya", the plural is"bilya". I would prefer the use of
the singular form, although I thinkthat a tendency will develop itself
naturally in the field and in the
texts to show what will be adopted as a pluralform in languages such as English. However,the same way latin words usually keep theirplural form of origin in English or French, we
can reasonably imagine the same for words of
Bantu origin.
Finally, I would like to counter those whowish to establish a link between "elya" or"bilya" with words meaning "to eat" or "food"in the languages spoken where Pan paniscus
can be encountered, and who find therefore theuse of "elya" or "bilya" as unsuitable. For a
non-experienced ear, the words involved mightseem related to each other. Although thismight have been the case, neither a zoologist,

Tab. 2 Words for 'chimpanzee' compared to words for 'eat' and 'food'6

an ecologist, nor a linguist should judge it.
Without entering a deep, linguistic explanation,
it is easy to show the difference between words
for Pan paniscus on one hand and those for "toeat" or "food" on the other (Tab. 2).
Although tones (marked by an accent
on vowels and enough to dissociate words
otherwise identical) are the same, one may
notice the variation of consonants and vowels
from a meaning to another. For a given
language, differences at the beginning of thewords are not taken into account, as they are
structural differentiate nouns from verbs for
instance.
I have brought here some linguistic
arguments to demonstrate the convenience of
the use of 'elya' to designate Pan paniscus. Of
course, this will not disrupt pure zoologicalestablishments. But taking such issue into
account is crucially important for local
research and actions, notably for what concerns
sustainable development. Besides moral injury,
neglecting or misusing local denominations offauna (or flora and local knowledge in general)can only be detrimental to scientific research.
It may lead to a lack of profound knowledge
about the distribution of species, their feeding,
habitat and behaviour.
REFERENCES
1. Kano T, Nishida T. 1999. Bilia as an authentic
vernacular name for Pan paniscus. Pan Africa
News 6: 1-3.
2. Tratz E, Heck H. 1954. Der afrikanische
Anthropoide “Bonobo”, eine neue
Menschenaffengattung. Saugetierk. Mitt. 2:
97-101.
3. Kortlandt A. 1993. Pygmy chimpanzee orbonobo?. Bulletin of the American Society ofPrimatologists 17: Letter to the Editor.
4. Ellington JE. 1977. Aspects of the Tiene
Language. University of Wisconsin, Madison.
5. Mamet M 1960. Le Langage des Bolia (Lac
Léopold II). MRAC, Tervuren.
6. Gilliard L. 1928. Grammaire Synthétique duLontomba. Editions de l’Essorial, Bruxelles,
Elisabethville.
7. Hulstaert G. 1957. Dictionnaire Lomongo Français. MRAC, Tervuren.
8. Mwanza N, Mulavwa M, Mola I, Yangozene
K. 2003. Confirmation of bonobo population

Pan Africa News, 13(1), June, 2006
around Lac Tumba. Pan Africa News 10:
29-31.
9. Van Everbroeck R. 1985. Dictionnaire
Lingala. Editions l’Epiphanie, Kinshasa.
10. Hochegger H. 1972. Dictionnaire Buma Français. Ceeba, Bandundu.
11. Rood N. 1958. Ngombe - Nederlands Frans Woordenboek. MRAC, Tervuren.
12. Hagendorens J. 1956. Dictionnaire Français- Otetela. Tshumbe-Ste-Marie.

<NEWS>
Grooming Hand Claspby Bonobos of Lui Kotal,
Democratic Republic of Congo.
B.I. Fruth1, G. Hohmann1, M.M. Beuerlein2
and W.C. McGrew2,3
1. Max Planck Institute for Evolutionary Anthropology
2. Dept. of Anthropology, Miami University
3. Leverhulme Centre for Human Evolutionary Studies andDept. of Biological Anthropology, University of Cambridge

INTRODUCTION

We report the first detailed sightings of thegrooming hand clasp (GHC) for the bonobo,
Pan paniscus, at Lui Kotal, in the Democratic
Republic of Congo. This distinctive variantof social grooming was first described for the
chimpanzee, P. troglodytes, at Mahale National
Park, Tanzania1, but has not been reported indetail before for any other species (but see 2 &3).
The field site of Lui Kotal is on the southwestern edge of the Salonga National Park (0245.6' S, 20 22.7' E) in Bandundu Province.
Research began in 20024 and has continued
uninterrupted to the present (May, 2006,
as of this writing). The study communityof apes has been partly habituated without
provisioning and does no crop raiding. They
live in mixed evergreen rain forest south of the
Lokoro River. Of the community of about 30
individuals, 12 have been visually identified
and genotyping is underway.
The grooming hand clasp was the firstsocial custom (in contrast to subsistence
activities) to be recognised in wild chimpanzees
and has been seen in five populations of P.
troglodytes across Africa from Ivory Coast toPan Africa News, 13(1), June, 2006
5,6

Uganda . Two individuals, usually adults, sit
facing one another in symmetric configuration
while grooming socially; they simultaneously
extend one arm vertically overhead and clasp
one another's hand or wrist in a mirror-image,'A-frame' posture. The other hand grooms
the revealed armpit or torso of the grooming
partner, and this mutual grooming mayalternate between hands and be interspersedwith normal grooming. Variation exists both
between groups and populations in the finedetails of the motor patterns, e.g. palm-to-palm
versus wrist-to-wrist clasping7,8.
The only previously published reports of
GHC in bonobos are from Wamba, where GHC
is said to be commonly observed, although
no details have been published2. At Lomoko,
Hohmann and Fruth 3 described what might
be called proto-GHC, in which one individual
lifts the hand of the other overhead duringgrooming. They distinguished between thisand GHC on grounds of lack of simultaneousgrooming, unilateral initiation, and lack ofritualisation.
OBSERVATIONS

On 24 March, 2006, MB, BF and WM
un-nested a party of bonobos at 05.45 hr. Its
composition was of at least 2 adult males, 3
adult females, 1 adolescent female, 1 juvenile
female, and 2 ventral infants. At 07.32 hr,
after eating nearby Gambeya lacourtiana andMammea africana fruits, the party travelled andforaged on the ground, giving us intermittent
visual contacts. Shortly after 8.00, they
stopped in an open clearing created by atreefall, a thick patch of terrestrial herbaceous
vegetation, mostly Haumania spp. There,
after eating pith, they settled down to rest andgroom for almost the next two hours. The
first grooming was seen at 08.13 and the last
behavioural datum was at 10.03; then they left,
unseen. Observation was unobstructed fromabout 20 m distance, but the thick vegetation
obscured their lower bodies as they sat in it,
except when they stood up to shift positions.
Notes were taken independently by the threeobservers, and then compared later.
At 08.35, one individual slowly and7deliberately raised its arm vertically overhead,
and about 2 sec later its grooming partner did
the same, and they clasped hands.
At 08.44, an adult female and adolescentfemale did the second GHC, which lasted for>60 sec. Both right arms were fully extended
and vertical, but the participants where visible
only from the shoulders upward. The GHC
was both preceded and followed by at least 5
min of normal social grooming. The shorterarm of the adolescent grasped the wrist of thelonger-armed adult, at the base of her palm; theadult’s wrist was fully flexed, hanging limp.
At 09.23, the same individuals did thethird GHC, repeating the form of the second,
but using their left hands. This bout of GHC
lasted about 52 sec. and was visible from only
the elbow upwards. It was notable that theclasping adolescent supported the combined
weight of both arms.
At 09.28, two individuals did an incipient
GHC, in which both arms were extended fully,
but were then retracted without making contact.
They continued normal social grooming.
At 09.40, another GHC occurred in which
only the two hands were seen raised overhead,as the participants had shifted downslope.
Again the clasp showed wrist support, and it
lasted <30 sec.
DISCUSSION

It is not clear from previous reports from
Wamba whether or not the GHC there wasidiosyncratic, habitual or customary; moredetails are needed. At Lui Kotal, GHC
is habitual or even customary (Fruth andHohmann, unpublished data). (Here, we
use 'habitual' and 'customary' in the senseof 9.) This ethnographic note is only astarting point, and further detailed data areneeded before ethnological comparisons canbe made (cf. 6). It remains to be seen for
GHC if cross-populational variation exists inbonobos (cf. 3), as it does in chimpanzees5,6.
Hohmann and Fruth3 described other crosssite differences in bonobo behaviour, in bothsocial and subsistence domains. Based on
our preliminary report, the form and functionof GHC in bonobo and chimpanzee seem to8

be similar, suggesting a pan-Pan behavioural
pattern.

Pan Africa News, 13(1), June, 2006
T, Reynolds V, Sugiyama Y, Tutin CEG,
Wrangham RW, Boesch C. 2001. Charting
cultural variation in chimpanzees. Behaviour
138:1481-1516.

ACKNOWLEDGMENTS

This research was supported by the
Max-Planck-Gesellschaft (GH), the Federal
Ministry of Education and Research (BF), andby Leakey Foundation and National Science
Foundation HOMINID funding to WCM. We
thank: L.F. Marchant for field assistance andcritical reading of the manuscript, ICCN for
granting permission to work at SNP, and thepeople of Lompole village for allowing us
access to the forest of their ancestors.
REFERENCES
1. McGrew W C, Tutin CEG. 1978. Evidence
for a social custom in chimpanzees? Man
13:234-251.
2. Nishida T, Kano T, Goodall J, McGrew
WC, Nakamura M. 1999. Ethogram andethnography of Mahale chimpanzees.
Anthropol Sci 107:141-188.
3. Hohmann G, Fruth B. 2003. Culture inbonobos? Between-species and withinspecies variation in behavior. Curr Anthropol
44:563-571.
4. Hohmann G, Fruth B. 2003. Lui Kotal—
a new site for field research on bonobos in
the Salonga National Park. Pan Africa News
10:25-27.
5. Nakamura M. 2002. Grooming hand-clasp in
Mahale M group chimpanzees: implications for
culture in social behaviours. In: Behavioural
Variation in Chimpanzees and Bonobos, eds.
C. Boesch, G. Hohmann, & L.F. Marchant,
Cambridge: Cambridge Univ. Press, pp. 71-83.
6 . M c G r e w W C . 2 0 0 4 . T h e C u l t u re d
Chimpanzee. Reflections on Cultural
Primatology. Cambridge: Cambridge Univ.
Press, 248 pp.
7. McGrew WC, Marchant LF, Scott SE andTutin CEG. 2001. Intergroup differences ina social custom of wild chimpanzees: thegrooming hand-clasp of the Mahale Mountains.
Curr Anthropol 42:148-153.
8. Nakamura M, Uehara S. 2004. Proximate
factors of different types of grooming-handclasp in Mahale chimpanzees: implications for
chimpanzee social customs. Curr Anthropol
45:108-114.
9. Whiten A, Goodall J, McGrew WC, Nishida<NOTE>A Louse Egg Left on a Leaf.
Koichiro Zamma
Primate Research Institute, Kyoto University

INTRODUCTION

Chimpanzees are known to squash
ectoparasites placed on the forearm1 (Taï, Côte
d'Ivoire), the palm2 (Bossou, Guinea), leaves1, 3(Gombe and Mahale, Tanzania), and to inspectthem on leaves4 (Budongo, Uganda). Although
it is difficult to identify ectoparasites due totheir small size, an adult louse, which wasrecovered from a leaf used in leaf-grooming
behavior, was identified3. I will report an egg
of a chimpanzee louse as the second identified
ectoparasite left on a leaf used for leafgrooming. I will also discuss the ectoparasite
removal techniques of chimpanzees who use
their teeth.
METHODS

Behavioral observation was conductedfrom August to November, 2003 at theMahale Mountains National Park, Tanzania. I
followed one of nine focal animals each day
and recorded grooming behavior on video
tape. I also focused on leaf-grooming behavior
by investigating whether ectoparasites orsomething else remained on the leaves used forleaf-grooming.
RESULTSI recovered a louse egg from a leaf used
for leaf-grooming by Orion, a 12-year-old
male. At 10:05:22 on August 21, 2003, Orionpicked up a leaf with his right hand after hefinished grooming Carter, an adult male. Oriontransferred a small object from his lower lip
to the leaf and folded the leaf using his rightPan Africa News, 13(1), June, 2006

9

Fig. 1. Egg of a chimpanzee louse. (a) Louse egg left on a leaf used for leaf-grooming byOrion. (b) Unhatched louse egg glued to chimpanzee hair. Tip of unhatched louse egg(upper arrow) is different from the hatched one (a).

hand and lower lip. He pressed the foldedside of the leaf with the thumb of his left hand,
opened the leaf, and returned the object to his
lower lip. After transferring the object fromhis lower lip to the leaf again, he accidentally
dropped the leaf. He picked up the leaf again
and tried to return the object to his lower lip.
After that he dropped the leaf and went away.
I recovered the leaf and found a louse egg left
on it (Fig. 1a).
The louse egg measured 1.0 x 0.4 mm (Fig.
1a). The louse egg had already hatched, andthe inside of the eggshell was empty. There
were no dents on the eggshell, although it
had been pressed between a folded leaf when
Orion leaf-groomed. The adhesive cementof the louse egg (indicated by arrow in Fig.
1a), which was attached to the chimpanzee
hair, had a bead shape. This indicates that thecement was not broken but was pulled throughthe hair.
Orion started grooming Carter's back at
10:04:33, 49 seconds before the leaf-grooming
described above. Orion stroked Carter’s hair
37 times with his hands and lips and touched
Carter’s back with his lips. At 10:05:09, Orionpinched and pulled Carter's hair between
his upper and lower teeth. It seemed that
he removed a louse egg stuck to a hair from
Carter's back. Then Orion stroked the hair
twice more with his left hand and stopped
grooming at 10:05:15. After that he turned
around, brought his hand to his mouth, andextracted something from it. It looked as if hepulled a hair with his hand and removed thelouse egg that was pinched between the upperand lower teeth. Then he started leaf-grooming(as described above).
DISCUSSION

It has been suggested that chimpanzees
remove ectoparasites such as lice and ticks5.
An adult louse, which was removed duringgrooming and handled during leaf-grooming,
was identified 3 . This study clarifies thatchimpanzees also have the skill to remove
louse eggs as well as adult lice. Japanesemacaques are known to have techniques
for handling louse eggs using the thumband finger 6, but it has not been confirmed
whether monkeys or apes can really remove
ectoparasites using the mouth and teeth. This
study also revealed that chimpanzees can use
their teeth to remove louse eggs.
The good shape of the eggshell refutes theidea that the middle of the egg was pushed out
when the chimpanzee squashed it in the folded
leaf. Therefore, the egg probably hatched
before Orion removed it. It is unnecessary to
remove hatched eggs from the viewpoint of thehygienic functions of grooming. Chimpanzees
may be incapable of discriminating between
hatched and unhatched eggs (Fig. 1b). In mycase, I could not judge whether the egg had
hatched without a microscope.

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Pan Africa News, 13(1), June, 2006

Why did Orion squash the louse egg in thefolded leaf? If the louse was in the adult stage,squashing and/or killing is a reasonable way toprevent it from parasitizing again. However,the louse egg was not likely to return to thehost again even if it was not crushed. I do
not know the reason. Orion might leaf-groom
as ritualized behavior following removing
movements.
ACKNOWLEDEGMENTS
This study was supported by a MEXT Grantin-Aid for JSPS Fellows.

in the southeastern corner of the Republic ofGuinea1. The core area of the group consistsof four small hills that are located about 4
km east from the Nimba Mountains. Dueto the small core area and large distance of
the Nimba Mountains, the Bossou group isthought to be geographically isolated fromothers. Secondary forests and abandoned fields
cover over the border between Guinea andLiberia. Here I report the first observed casein which Bossou chimpanzees actually crossed
the national border into the Liberian forest.
Locations were recorded by GPS.
OBSERVATIONSREFERENCES
1. Boesch C. 1995. Innovation in wild
chimpanzees (Pan troglodytes). Int J Primatol
16: 1-16.
2. Nakamura M, Nishida T. 2006. Subtle
behavioral variation in wild chimpanzees,
with special reference to Imanishi’s concept ofkaluchua. Primates 47: 35-42.
3. Zamma K. 2002. Leaf-grooming by a wild
chimpanzee in Mahale. Primates 43: 87-90.
4. Assersohn C, Whiten A, Kiwede ZT, Tinka
J, Karamagi J. 2004. Use of leaves to inspectectoparasites in wild chimpanzees: a third
cultural variant? Primates 45: 255–258.
5.Goodall J. 1968. The behaviour of free living
chimpanzees in the Gombe Stream Reserve.
Anim Behav Monogr 1: 161-311.
6. Tanaka I, Takefushi H. 1993. Eliminationof external parasites (lice) is the primaryfunction of grooming in free-ranging Japanesemacaques. Anthropol Sci 101: 187-193.

<NOTE>
Bossou Chimpanzees Crossed
the National Border of Guinea
into Liberia.
Gaku Ohashi
Primate Research Institute, Kyoto University

INTRODUCTION

Since 1976, a group of wild chimpanzees
has been studied at Bossou, which is locatedAt 7:23, on February 14th, 2006, elevenchimpanzees, including my focal individual(PE, an adolescent male), were found eating
Myrianthus libericus fruits (7°38'19.3" N, 8°
30'48.0" W). Next, they rested on the groundfor a while. At 8:29, they started to move on
the ground. Due to the heavy bush, the local
assistants and I lost the chimpanzees at 8:39.
At 10:47, we found the focal chimpanzee
again (7°38'07.7" N, 8°30' 55.2" W). The
party consisted of six chimpanzees: three adultmales (TA, FF, and YL), two adult females(Pm and Yo), and one adolescent male (PE).
They were resting on the ground, but they soon
started to move. At 10:58, the six chimpanzees
entered a swamp, and ate Nephrolepis biserrata
leaves for about 5 minutes (7°38'09.7" N, 8°
30'57.6" W). They moved again and arrived ata pineapple field (7°37'53.9" N, 8°31'11.8" W).
The field is located on the western slope of ahill called Zono, which Bossou chimpanzees
often visit during consortship periods. For
about 10 minutes, they ate pineapple fruit
before entering the forest. At 11:46, three
chimpanzees (YL, Yo, and Pm) started to
eat Pseudospondias microcarpa fruit, and theother chimpanzees rested on the ground (7°37'56.3" N, 8°31'13.1" W). At 12:23, the six
chimpanzees climbed the hill, and arrived
at another Pseudospondias microcarpa tree at
12:52 (7°37'45.0" N, 8°31'27.6" W). They
ate fruit and rested in the tree. At 14:14, theystared to move on the ground again. On theway, at 14:43, Yo started to eat PennisetumPan Africa News, 13(1), June, 2006

11

Fig. 1. Survey map of Guinea and Liberia (modified from Google Earth image).

purpureum pith, but the other five chimpanzees

continued to travel (7°37'36.7" N, 8°31'30.8"
W). The five chimpanzees entered the primary
forest at the Gba village, Guinea. Gba is on
the border with Liberia. At 15:27, three adultmales (TA, FF, and YL) uttered pant-hoot,climbed trees, and traversed a valley. Since theforest over the valley appeared to be a sacredarea of the village, we stopped following themat 15:29 (7°37'03.6" N, 8°31'57.3" W).
On February 15th, we looked for the
chimpanzees in the Gba village. We found
six beds there (7°36'57.0" N, 8°31'56.3" W).
Judging from the fresh feces under the beds,
they apparently slept there from the evening of
the 14th to morning (Fig. 1, beds on the 14th).
When we visited the hill near the Liberianborder, we found feces at the top (7°36'58.2"
N, 8°31'57.3" W), but we could not find any
chimpanzees in the Gba village.
On February 16th, six new beds (Fig. 1,
beds on the 15th), fresh traces, and feces were

found in the forest at New-Yekepa, Liberia (7°35'45.8" N, 8°31'59.1" W). Judging from thetraces, the chimpanzees appeared to have eaten
sugar cane pith, Parkia fruit, Landolphia fruit,
Myrianthus fruit, pineapple fruit, Aframomum
pith and fruit, and palm petiole. We also found
two old beds (7°36'00.1" N, 8°31'47.3" W. Fig.
1, old beds).
On February 17th, four new beds wereconfirmed in the Gba forest (7°36'57.3" N, 8°
31'53.4" W. Fig. 1, beds on the 16th). Judging
from the beds, the six chimpanzees returnedto the Guinean side on the evening of the16th.
At 13:23, TA, Pm, and PE were observed
eating Morus mesozygia fruit at the core areaof Bossou (7°38'30.1" N, 8°30'26.7" W). At
14:58, all six chimpanzees were confirmed in
the same Morus tree.
DISCUSSIONIn February, fruits were abundant in

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Pan Africa News, 13(1), June, 20062

the forest at Bossou . Actually many trees
bore their fruits, including Pseudospondias
microcarpa, Morus mesozygia, Parkia bicolor,
and Myrianthus libericus. The chimpanzees
apparently did not travel to the peripheralarea due to a lack of food. There are manysugar cane plantations in Liberia for distilling
alcohol. Possibly their strong preference
toward sugar cane tempted the chimpanzees
into the Liberian forest.
Old beds were also found in the forest at
New-Yekepa, Liberia. It suggests that Bossou
chimpanzees had previously visited the forest.
In this case, the chimpanzees only stayed in
Liberia for two days. Due to the short stay andthe difficulty of observation on the peripheral
areas, researchers have probably missed
traveling patterns.
According to the local people, chimpanzees
exist in the northern part of Liberia. However,the distribution of chimpanzees there isalmost unknown. Bossou chimpanzees may
emigrate from Guinea to Liberia. As well as
in Ivory Coast3, further extensive survey andconservation effort are needed in Liberia.
ACKNOWLEDEGMENTS

This study was financed by a MEXT Grant-

in-Aid for Specially Promoted Research(nos.12002009, 16002001 to T. Matsuzawa),
and a Grant-in-Aid for JSPS Research Fellow(no. 160896 to G. Ohashi).
REFERENCES
1.Sugiyama Y, Koman J. 1979. Social structureand dynamics of wild chimpanzees at Bossou,
Guinea. Primates 20: 323-339.
2.Yamakoshi G. 1998. Dietary responses tofruit scarcity of wild chimpanzees at Bossou,
Guinea: Possible implications for ecologicalimportance of tool use. Am J Phys Anthropol
106: 283-295.
3.Humle T, Matsuzawa T. 2001. Behavioural
diversity among the wild chimpanzee
Pan Africa News, Vol. 13, No.1
Published in June, 2006
Address:
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