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MARCH 2022
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VOL. 28, NO. 2

Contents<Note>
Indirect evidence of tool-assisted hunting in the
Bantan chimpanzee (Pan troglodytes verus) community in southeastern Senegal savanna-woodlands
Kristine N. Micheletti, William D. Aguado,
Papa Ibnou Ndiaye, Jill D. Pruetz		
14<Note>First observation of fellatio by a wild non-estrus adultfemale chimpanzee on an adult male, and subsequent
meat sharing in Mahale
Kenichiro Hikida				17<Letter>
MWCS under COVID-19 crisis

Kazuhiko Hosaka			21<Book Info>
Chasing after Chimpanzees: The Making of aPrimatologist				22

Pan Africa News, Vol. 28, No.2
Published in March. 2022
Address: c/o Human Evolution Studies,
Dept. of Zoology, Faculty of Science,
Kyoto Univ., Kyoto, 606-8502, JAPANTEL: (+81)75-753-4108
FAX: (+81)75-753-4115
E-mail: pan.editor@gmail.com
URL: http://mahale.main.jp/PAN/
ISSN: 1884-751X (Print), 1884-7528 (Online)

13Pan Africa News, 28(2):14–16 (2022)

Note

Indirect evidence of tool-assisted hunting in the Bantan
chimpanzee (Pan troglodytes verus) community in southeastern
Senegal savanna-woodlands
Kristine N. Micheletti1 , William D. Aguado1, Papa Ibnou Ndiaye2,
Jill D. Pruetz3✉✉

1 Department of World Languages and Cultures, Anthropology Program, Iowa State University, USA
2 Département de Biologie animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Sénégal
3 Department of Anthropology, Texas State University, USA(✉ E-mail: kristine_micheletti@yahoo.com, pruetz@txstate.edu)

ABSTRACT

Chimpanzees use tools extensively, but tool-assisted hunting has been reported at only two sites thus far. Systematic
tool-assisted hunting has only been recorded at the Fongoli site in Senegal, where hundreds of cases have been recordedof chimpanzees using tools to hunt bushbaby (Galago senegalensis) prey. Here, we report a putative case of tool-assisted
hunting at the Bantan study site in southeastern Senegal, based on indirect evidence of tools and tool-making traces ina context similar to that observed at neighboring Fongoli chimpanzee community. If our interpretations are correct, thesimplest explanation is that Fongoli females have dispersed to this neighboring community, bringing with them the behavior of tool-assisted hunting. However, the persistence and frequency of tool-assisted hunting at other sites in Senegal
is still unknown. Tool-assisted hunting in the Bantan chimpanzee community would present only the third such knownsite for such behavior among wild chimpanzees thus far.
Keywords: tool-use, chimpanzees, hunting, savanna, Senegal

INTRODUCTION

The use of tools by non-human animals sheds light on
their cognitive abilities (Seed & Byrne 2010) and propensity for material culture (Whiten et al. 1999; van Schaik et
al. 2003). Chimpanzees (Pan troglodytes) are particularly
prolific tool-users that are adept at manufacturing andusing tools to obtain food. Chimpanzees commonly use
tools to extract invertebrate prey from otherwise inaccessible locations (e.g., “termite fishing” and “ant dipping”:
Goodall 1964; McGrew 1974). One chimpanzee community—the Fongoli community of Senegal—commonly
hunts mammalian prey with the aid of tools (Pruetz &Bertolani 2007; Pruetz et al. 2015), though chimpanzeesof Mahale, Tanzania (M-group) have also been reported tohunt a squirrel and hyrax with tools (Huffman & Kalunde
1993; Nakamura & Itoh 2008). Tool-assisted hunting ina non-human primate is particularly relevant to paleoanthropology because tool-use and hunting have long
been considered as critical developments during human
evolution (Hill 1982). Additionally, this type of hunting
is significant to understanding the evolution of hunting
in early hominids, as bipedal apes were likely less adept
at hunting prey such as monkeys, the main vertebrate
prey of chimpanzees inhabiting forested environments(Pickering & Domínguez-Rodrigo 2012). Although hunting with tools is characteristic of the Fongoli group, it isunknown whether neighboring chimpanzee communities
also engage in this behavior. Evidence that nearby chimpanzee groups hunt with tools could provide insight into
the scope of behavioral continuity between chimpanzee

populations and may help to better understand the spreadof socially-learnt traditions in non-human primates. It
may also be germane to parsing out the environmentalpressures that gave rise to this unusual behavior observed
at Fongoli.
Tool-assisted hunting bouts at Fongoli generally occur
through a systematic process during which chimpanzees 1)
locate a potential Galago senegalensis nest cavity in thehollow of a tree trunk or branch, 2) locate a branch to suitably jab into the cavity, 3) modify the branch by stripping
it and/or trimming the ends, and 4) jabbing it repeatedly
into the cavity to rouse its prey from the nest or injure
it, whereupon it is captured by hand and eaten (Pruetz &Bertolani 2007). While this behavior remains rare outsideof Fongoli, similar reports have been recorded at Mahale,
in which chimpanzees were found to extract mammalianprey from tree and rock dens with sticks for consumption(Huffman & Kalunde 1993; Nakamura & Itoh 2008).
Tool-assisted hunting has been recorded more than
500 times at Fongoli (Pruetz unpublished data). Most
chimpanzees at Fongoli, excluding young infants, havebeen observed to hunt with tools, and females do so relatively more frequently than males (Pruetz et al. 2015).
Individuals appear to improve in their success with practice, suggesting some degree of observational learning.
Most tool-assisted hunting at Fongoli occurs during thewet season from June to September, with some cases also
occurring in the transitional months of May and October.
The seasonality of tool-assisted hunting, in addition to thepatterned tool modification and implementation process,14Pan Africa News, 28(2):14–16 (2022)
suggests that this is a regular foraging technique within
the Fongoli community, rather than isolated, trial-anderror events.
Here, we present the first putative evidence of toolassisted hunting of mammalian prey among unhabituatedchimpanzees, the Bantan community, which neighbors
the Fongoli group. We discuss the implications of thisfor understanding the spread of socially-learnt traditions
among chimpanzees and the scope of tool-use in primates
more generally.

METHODS

which can deviate by any degree through the survey area
(Kühl et al. 2008). Additionally, we systematically surveyed forested habitats (e.g., gallery forest and woodland
stream areas) where nests and other signs of chimpanzees
were thought to be most concentrated. Any evidence oftool-use was recorded, along with the GPS location, thehabitat type it was found in, and the type of tool. Tools
were brought back to camp, laid flat, and measured fromtip to tip.

RESULTS

Two hunting tools were identified by a resemblance
to those used by Fongoli chimpanzees in terms of theirdeposit location, patterns of use-wear, patterns of modification in tool creation, size, and shape (Figure 1).
Hunting tools were sticks found in association withfreshly removed leaves and twigs and were situated in
the vicinity of possible Galago nesting cavities. Bothhunting tools were found near each other in a woodland
habitat and are from the species Cordyla pinnata (Figure
1; Micheletti 2018). Woodland habitats are common locations of tool-assisted hunting by Fongoli chimpanzees,
where Pterocarpus erinaceus and Terminalia sp. trees
are common and where Galago nesting cavities are frequently located (Pruetz unpublished data). The first tool
was discovered under an Anogeissus leiocarpus tree, near
the trunk, with a diameter at breast height of 33.4 cm anda visible cavity that may have been used by galagos. The
Data Collection
second tool was found about five meters away on a termite
The focus during the study, lasting from May through mound, which showed no signs of recent termite-fishing
August 2017, was to survey for signs of chimpanzees in behavior. The second tool was found in close proximity tothis area and to assess any anthropogenic threats to them the Anogeissus tree crown, similar to what is seen at the(Micheletti 2018). Sixteen reconnaissance walks were Fongoli site when ‘spear’ tools are discarded. All huntconducted to find evidence of chimpanzee´s presence. ing, termite fishing, and ant dipping tools were found in
Reconnaissance walks consist of surveying by foot in a the eastern side of the Bantan community’s range based
predetermined direction along a path of least resistance, on 2017 nesting data (Micheletti 2018). Furthermore, thehunting tools were found on June 22,
which is considered the wet season,
and when most tool-assisted hunting practices are observed at Fongoli(Pruetz et al. 2015).
These tools were within therange of Fongoli hunting tool size,
which average 10.1 mm in width at
midpoint of the tool (n = 223 tools)
and 64.6 cm in length (n = 298 tools),
being noticeably longer, thicker, andstraighter than termite and ant dipping tools, which are on average lessthan 5 mm in width (Pruetz unpublished data). Both putative hunting
tools (n = 2; tool 1 = 83.1 cm, tool 2= 113.9 cm, sd=31.8) fell within therange of tool lengths recorded for
the Fongoli community (40–120 cm;
Pruetz & Bertolani 2007). The tools
showed sites of detachment damage
indicated by areas of stripped bark,Figure 1. Putative hunting tool in situ with trimmed branches (green leaves inconsistent with side branches being
top of photo) and binoculars for scale (a); end of tool with wear pattern (b); andpulled off, as is commonly observed
scar on the edge of the tool, typical of removal of side branches and leaves (c).
Scar is ~13 cm in length. Photo (a) by J.D.P and photos (b) and (c) by K.N.M.
in hunting tools made by Fongoli
Study Site and Subjects
The Bantan site lies adjacent to and northwest of the
Fongoli community in southeastern Senegal, approximately 17 km north/northwest of the town of Kedougou,
at 12°45.06325N, -12°15.425983W. This is a savanna mosaic habitat, including woodland, grassland, gallery forest
and bamboo woodland habitat types (Pruetz et al. 2002).
The Bantan chimpanzee community is an unhabituated group that has been sporadically studied via indirect
observational methods since 2000. There are estimatedto be approximately 20 individuals in the group, based on
nesting data collected in previous studies (Pruetz unpublished data; Micheletti 2018). Ndiaye and students havebeen conducting research on this community since 2016
(Ndiaye et al. 2018; Diallo 2019).

15

Pan Africa News, 28(2):14–16 (2022)

Haslam M, Hernandez-Aguilar RA, Ling V et al. 2009.
Primate archaeology. Nature 460:339–344.

chimpanzees (Figure 1; Pruetz & Bertolani 2007).

https://doi.org/10.1038/nature08188

DISCUSSION

Haslam M, Her nandez-Aguilar R A, Proff itt T et al.
2017. Primate archaeology evolves. Nature Ecol Evol
1:1431–1437.

We report finding modified sticks within the rangeof the Bantan chimpanzee community in Senegal, interpreted as putative chimpanzee hunting tools. As such, ourstudy extends the record for the rare tool-assisted hunting
behavior and contributes to the growing field of primate
archaeology (Haslam et al. 2009; Haslam et al. 2017) thatstrives to find links between the material culture of nonhuman primates and their behavior. Our interpretations on
the function of the purported tools are based on multiple
similarities to known hunting tools of the adjacent Fongoli
chimpanzee community. As at Fongoli, these modified
sticks were found near potential Galago nesting sites, they
are within the size range of Fongoli hunting tools and exhibited similar modification and use-wear patterns (Pruetz& Bertolani 2007). It is unlikely that the putative hunting
tools were made by Fongoli chimpanzees given the location of the site, northwest of the Fongoli chimpanzee core
range.
This form of tool-use could be carried between chimpanzee communities through dispersal and could be widespread in Senegal. Adolescent females may spread thisbehavior between communities upon dispersal, given thatat Fongoli, females hunt with tools relatively more frequently than males (Pruetz & Bertolani 2007; Pruetz et al.
2015). It is probable that females from the Fongoli community brought this behavior to the neighboring Bantan
community, or vice versa.
Continued research on their tool technology canhelp to answer questions regarding chimpanzee tool-use,socially-learnt traditions, and learning processes. Suchtransfer of knowledge may provide insights into primate
learning processes.

https://doi.org/10.1038/s41559-017-0286-4

Hill K 1982. Hunting and human evolution. J Hum Evol
11:521–544.
https://doi.org/10.1016/S0047-2484(82)80107-3

Huffman MA & Kalunde MS 1993. Tool-assisted predation on a squirrel by a female chimpanzee in the Mahale
Mountains, Tanzania. Primates 34:93–98.
https://doi.org/10.1007/BF02381285

Kühl H, Mundry R, Boesch C et al. 2008. Best Practice
Guidelines for Surveys and Monitoring of Great Ape
Populations. IUCN SSC Primate Specialist Group (PSG),
Gland, Switzerland.
https://doi.org/10.2305/IUCN.CH.2008.SSC-OP.36.en

McGrew WC 1974. Tool use by wild chimpanzees in feeding
upon driver ants. J Hum Evol 3:501–508.
https://doi.org/10.1016/0047-2484(74)90010-4

Micheletti K 2018. Influence of Human Disturbance on
Western Chimpanzee ( Pan troglodytes verus) Nesting
Behavior in a Savanna Mosaic Habitat, Southeastern
Senegal. (Master’s Thesis, Iowa State University).
Nakamura M, Itoh N 2008. Hunting with tools by Mahale
chimpanzees. Pan Afr News 15:3–6.
https://doi.org/10.5134/143489

Ndiaye PI, Lindshield S, Badji L et al. 2018. Survey of chimpanzees (Pan troglodytes verus) outside protected areas insoutheastern Senegal. Afr J Wild Res 3:1–14.
https://doi.org/10.3957/056.048.013007

Pickering TR, Domínguez-Rodrigo M 2012. Can we use
chimpanzee behavior to model early hominin hunting? In: Stone Tools and Fossil Bones: Debates in the
Archaeology of Human Origins. Domínguez-Rodrigo M(ed), Cambridge University Press, Cambridge, pp. 174–197.
Pruetz JD, Bertolani P 2007. Savanna chimpanzees, Pantroglodytes verus, hunt with tools. Curr Biol 17:412–417.
https://doi.org/10.1016/j.cub.2006.12.042

Pruetz JD, Bertolani P, Boyer Onto K et al. 2015. New
evidence on the tool-assisted hunting exhibited by chimpanzees (Pan troglodytes verus) in a savannah habitat at
Fongoli, Sénégal. R Soc Open Sci 2.

ACKNOWLEDGEMENTS

https://doi.org/10.1098/rsos.140507

We thank the Direction des Eaux, Forêts, Chasses etde la Conservation des Sols for permission to conduct thisresearch in Senegal. We would like to thank Dondo Kanté,
Jacques Keita, Michel Sadiakho, and the Camara family.
Funding for this work was provided by the Department
of World Languages and Cultures, Iowa State University,and the Center for Global and Regional Environmental
Research, University of Iowa.

Pruetz JD, Marchant LF, Arno J et al. 2002. Survey of savanna chimpanzees (Pan troglodytes verus) in southeastern
Senegal. Am J Primatol 58:35–43.

REFERENCES

Whiten A, Goodall J, McGrew WC et al. 1999. Cultures inchimpanzees. Nature 399:682-685.

https://doi.org/10.1002/ajp.10035

Seed A, By r ne R 2010. A nimal tool-use. Curr Biol
20:R1032–R1039.
https://doi.org/10.1016/j.cub.2010.09.042

van Schaik CP, Ancrenaz M, Borgen G et al. 2003.
Orangutan cultures and the evolution of material culture.
Science 299:102–105.
http://dx.doi.org/10.1126/science.1078004

Diallo B 2019. Etude du Comportement de Nidification du
Chimpanzé de l’Afrique de l’Ouest, Pan troglodytes verus
à Bantankiline (Kédougou, Sénégal). Master´s Thesis in
animal biology, Université Cheikh Anta DIOP de Dakar(Sénégal).
Goodall J 1964. Tool-using and aimed throwing in a community of free-living chimpanzees. Nature 201:1264.

https://doi.org/10.1038/21415

Received: 3 December 2021
Accepted: 13 January 2022

https://doi.org/10.1038/2011264a0

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Pan Africa News, 28(2):17–20 (2022)

Note

First observation of fellatio by a wild non-estrus adultfemale chimpanzee on an adult male, and subsequent meat
sharing in Mahale
Kenichiro Hikida✉

Graduate School of Science, Kyoto University, Japan(✉ E-mail: hikida.kenichirou.54e@st.kyoto-u.ac.jp)

ABSTRACT

Sociosexual behaviors such as mounting and genital touch have been extensively reported in chimpanzees.
However, there are a small number of reported cases of fellatio, with only a few cases between captive juveniles or adultmales. In this study, fellatio from a non-estrus adult female to an adult male holding bushpig meat were observed forthe first time. After a series of sociosexual behaviors including fellatio, the meat was shared through begging behavior
from the female to the male, suggesting that the series of displayed sociosexual behaviors may have occurred to reduce
tension, so that the female could then make a smooth transition to begging behaviors. In addition, the fact that fellatio
displayed between male and female in a context similar to previously reported cases of fellatio between adult males
suggests that the social bond-strengthening effect of fellatio can also function between an adult male and female.

Keywords: Pan troglodytes schweinfurthii, Mahale Mountains National Park, sociosexual behaviors, fellatio, meat
sharing

INTRODUCTION

In primates, sociosexual behaviors without mating
have been observed in both opposite-sex and same-sex
partners. Some of these examples include mounting without penile penetration in the olive baboon (Papio anubis)(Owens 1976) and in the Japanese macaque (Macaca
fuscata) (Takahata 1982), and anal penetration between
males in the Geoffroy’s spider monkey (Ateles geoffroyi) (Busia et al. 2018) and in the snub-nosed monkey(Rhinopithecus roxellana) (Fang et al. 2018).
Although the forms and frequencies of sociosexual
behaviors may vary among taxa, they appear to serve social functions. Such behaviors can appear in a variety ofcontexts, such as mating practices (the Japanese macaque:
Gunst et al. 2013), negotiation of dominance relations (thesnub-nosed monkey: Huang et al. 2017), and reducing
social tension after aggression or during food sharing (thebonobo [Pan paniscus]: de Waal 1990; Hohmann & Fruth,
2000).
Although chimpanzees (Pan troglodytes) engage insociosexual behavior less frequently than bonobos (Woods& Hare 2011; Gruber & Clay 2016), it has been extensively reported (Crawford 1942; Kutsukake & Castles
2004; also see a review by Sandel & Reddy 2021). The
frequently reported behavioral types in chimpanzees
are mounting and touching of genitals (including mutual
touching). However, there are few reported cases of fellatio, or mouthing of the male penis by another individual.
Some acts of fellatio are directed to still immature males
as reported by Malick & Savage (1977) and SavageRumbaugh & Wilkerson (1978) who noted oral-genital
contacts among captive juvenile chimpanzees in the con-text of play. Nishida (1981) reported that an adult femaleat Mahale mouthed her weaning male offspring’s penis
as means of appeasing his frustration. Only two reported
cases of fellatio were performed on adult males, and bothwere by other males to reduce tension, one among captive chimpanzees in Primate Foundation of Arizona in
the USA (Shefferly & Fritz 1992) and the other among
sanctuary-living chimpanzees in Chimfunshi Wildlife
Orphanage in Zambia (Brooker et al. 2020). To the best of
my knowledge, there have been no reports of fellatio byan adult female chimpanzee on an adult male.
This study reports the first such case and describes
other accompanying sociosexual behaviors, the context,
and subsequent meat sharing.

METHODSThis case was observed between chimpanzees ofthe M group in the Mahale Mountains National Park,
Tanzania, on September 20, 2019 (see Nakamura et al.
2015 for details of the study site). The case was recorded
first on a field note and subsequently with a video camera(Panasonic HC-W585M). An adult male named Darwin(DW) and an adult female named Fawn (FW) were theparticipants in this event. FW had borne an infant thatyear and thus was non-estrous.

OBSERVATIONS

At 08:35 h on September 20, 2019, a large party of
the M-group chimpanzees ranged southeast of the area
called K1, less than 1 km from the researchers’ camp, andDW was followed. At 08:53 h, DW was holding a freshcarcass of a bushpig (Potamochoerus larvatus) piglet. At

17

Pan Africa News, 28(2):17–20 (2022)

08:54 h, after climbing a nearby tree, he started eating
meat from the bushpig. At 08:58 h, FW with the infant attached to her belly appeared from an unknown location,
climbed the same tree, and sat on a lower branch in frontof DW. No other individuals were observed in the vicinity. Because a clear view of the subjects was not possible,
at 08:58 h the observation location was changed and video
recording begun at 09:01 h (Video 1 available online at
http://mahale.main.jp/PAN/2021/005.html; hereinafter,
times in descriptions from video footage are given inhours:minutes:seconds).
At 09:02:04 h, FW touched the erect penis of DW
with her left hand for 3 s. Her face was not visible as herback was turned to the camera, but judging from the direction of the head, it is assumed that her gaze was not on
DW’s penis but on his hand holding the piglet. DW continued to eat without any significant reaction. At 09:02:07 h,
FW mouthed DW’s penis for 3 s (Figure 1). She touched
DW’s penis again for 3 s, this time pinching it with herleft thumb and index finger. At 09:02:22 h, FW presented
her rump to DW and pressed her non-swollen sexual skinagainst DW’s erect penis for 4 s (Figure 2). No penile penetration occurred. FW reached toward DW’s hand holding
the piglet at 09:02:27 h, but he moved it away from her. At
09:02:31 h, DW turned his back completely on FW. Then,
at 09:02:40 h, FW moved to face DW, and at 09:02:51 h,
she reached for his mouth and hand holding the meat
while peering into his face. At 09:03:22 h, FW loosely
grabbed DW’s hand holding the meat. At 09:03:34 h,

FW grinned, pant-screamed slightly, and then reached
for the meat. FW eventually obtained a small amount ofmeat which DW had removed from his mouth. DW thenclimbed further up the tree and left FW, ending the interaction, at 09:03:51 h.

DISCUSSION

In the present case, a non-estrus female, FW, after
several types of sociosexual behaviors, such as touching
the penis, fellatio, and genito-genital contact without penile insertion, begged DW for bushpig meat by extending
her hand to the mouth of DW. This is the first such reportof fellatio between opposite-sex adult chimpanzees andis also the first report of fellatio in the context of foodsharing.
Sociosexual behaviors during food sharing have beenreported in wild chimpanzees and have been interpreted
as actions performed to reduce social tension (Sandel &Reddy 2021). Thus, it can be assumed that the series ofsociosexual behaviors in this report also served to reduce
tension. Alternatively, such behavior may function as begging, because typical begging behaviors, such as peering
into the face and reaching for the mouth, also occurred.
Gilby (2006), who studied begging behaviors during
meat sharing, classified them according to their intensity,from milder to more intense: (1) sitting close to the meat
holder and peering at him, (2) reaching out to the meat
holder (no contact), (3) touching the meat holder, and (4)reaching a hand near to the meat holder’s mouth and mak-Figure 1. Fellatio between FW (right) and DW (left)

Figure 2. FW (right) pressing her sexual skin to DW’s (left) erect penis

18Pan Africa News, 28(2):17–20 (2022)

ing contact with it. The series of sociosexual behaviors
observed in this study, if they were considered begging
behaviors, would be classified as category (3). However,
several behavioral elements observed in this study were
not reported in Gilby’s behavioral repertoire of begging.
In addition, according to Gilby’s definition of harassment
during meat-eating, the observed behaviors were not considered harassment, because there was no contact with
DW’s mouth or hands, nor was his behavior restricted.
Although it is difficult to conclude from just one case, theseries of displayed sociosexual behaviors may have occurred to reduce tension, so that FW could then make asmooth transition to begging behaviors.
The connection between meat sharing and sexual
behavior in these observations may seem relevant to themeat-for-sex hypothesis (Stanford 1996), especially regarding reciprocation on a long-term basis (Gomes andBoesch 2009). In this case, however, it is unlikely that
there was an immediate reciprocal exchange of meat sharing and mating opportunities for two reasons. The firstis that the female was non-estrous and lactating, whichmeans copulating with her would not lead to pregnancy.
The second is the negative responses of DW, such as turning away after a series of sociosexual behaviors. In thiscase, even though meat sharing occurred after the begging behaviors, it appeared unlikely that DW gave meat in
immediate return for the sociosexual behaviors of FW.
Fellatio is considered rare because males are at highrisk of exposing their vital organs to other chimpanzees’
mouths. It has been proposed that such high-risk behaviors can be used to test and strengthen alliances between
same-sex partners (Kirkpatrick 2000). For chimpanzee
males, forming alliances with other males is crucial.
Thus, for a rare case of male–male fellatio, such a function of strengthening male–male relationships was emphasized (Brooker et al. 2020). However, as reported inthis study, fellatio can occur between a female and a malein the probable context of tension reduction. Thus, thefunction that is used to test social bonds may also apply to
opposite-sex partners.
This report describes a very rare case of heterosexualfellatio observed in the wild. However, it is difficult toknow why such behaviors are rare and why this case occurred in this context. More such observations are needed
to gain a deeper understanding of sociosexual behaviors
as well as the function of fellatio in chimpanzees.

sent study was financially supported by JSPS KAKENHI#2019J23191 and #4903 (JP17H06381).

REFERENCES

Brooker JS, Webb CE, Clay Z 2020. Fellatio among malesanctuary-living chimpanzees during a period of social
tension. Behaviour 158: 77–87.
https://doi.org/10.1163/1568539X-bja10053

Busia L, Denice AR, Aureli F, Schaffner CM 2018.
Homosexual behavior between male spider monkeys (Ateles
geoffroyi). Arch Sex Behav 47: 857–861.
https://doi.org/10.1007/s10508-018-1177-8

Crawford MP 1942. Dominance and the behavior of pairs offemale chimpanzees when they meet after varying intervals of separation. J Comp Psychol 33: 259–265.
https://doi.org/10.1037/h0060471

de Waal FBM 1990. Sociosexual behavior used for tension
regulation in all age and sex combinations among bonobos. In: Pedophilia. Feierman JR (ed) Springer, Berlin, pp.
378–393.
https://doi.org/10.1007/978-1-4613-9682-6_15

Fang G, Dixson AF, Qi XG, Li BG 2018. Male–male mounting behaviour in free-ranging golden snub-nosed monkeys(Rhinopithecus roxellana). Folia Primatol 89: 150–156.
https://doi.org/10.1159/000487004

Gilby IC 2006. Meat sharing among the Gombe chimpanzees: harassment and reciprocal exchange. Anim Behav 71:
953–963.
https://doi.org/10.1016/j.anbehav.2005.09.009

Gomes CM, Boesch C 2009. Wild chimpanzees exchangemeat for sex on a long-term basis. PloS ONE 4: e5116.
https://doi.org/10.1371/journal.pone.0005116

Gruber T, Clay Z 2016. A comparison between bonobos andchimpanzees: a review and update. Evol Anthropol 25:
239–252.
https://doi.org/10.1002/evan.21501

Gunst N, Leca JB, Vasey PL 2013. Development of sexualand socio-sexual behaviours in free-ranging juvenile male
Japanese macaques, Macaca fuscata. Behaviour 150:
1225–1254.
https://doi.org/10.1163/1568539X-00003088

Hohmann G, Fruth B 2000. Use and function of genital contacts among female bonobos. Anim Behav 60: 107–120.
https://doi.org/10.1006/anbe.2000.1451

Huang P, He X, Zhang E, Chen M 2017. Do same-sex mounts
function as dominance assertion in male golden snubnosed monkeys (Rhinopithecus roxellana)? Am J Primatol
79: e22636.
https://doi.org/10.1002/ajp.22636

Kirkpatrick RC 2000. The evolution of human homosexual
behavior. Curr Anthropol 41: 385–413.
https://doi.org/10.1086/300145

Kutsukake N, Castles DL 2004. Reconciliation and postconflict third-party affiliation among wild chimpanzees in
the Mahale mountains, Tanzania. Primates 45: 157–165.
https://doi.org/10.1007/s10329-004-0082-z

Malick C, Savage E 1977. Play and socio-sexual behaviour ina captive chimpanzee (Pan troglodytes) group. Behaviour
60: 179–194.

ACKNOWLEDGEMENTS

https://doi.org/10.1163/156853977X00324

I would like to thank the Tanzania Wildlife ResearchInstitute (TAWIRI), Tanzania Commission for Scienceand Technology (COSTECH), and Tanzania National
Parks (TANAPA) for permission to conduct this research. I am grateful to the Mahale Mountains National
Park (MMNP) and Mahale-Gombe Wildlife ResearchCentre (MGWRC) for their logistic support. I thank allcolleagues and local assistants of the Mahale Mountains
Chimpanzee Research Project (MMCRP) for their continuous help and support. I would like to thank Editage(www.editage.com) for English language editing. The pre-Nakamura M, Hosaka K, Itoh N, Zamma K (eds) 2015.
Mahale Chimpanzees: 50 Years of Research. Cambridge
University Press, Cambridge.
Nishida T 1981. [The World of Wild Chimpanzees]. Chuko
Shinsho, Tokyo, in Japanese.
Owens N 1976. The development of sociosexual behaviour infree-living baboons, Papio anubis. Behaviour 57: 241–258.
https://doi.org/10.1163/156853976X00541

Sandel AA, Reddy RB 2021. Sociosexual behaviour in wild
chimpanzees occurs in variable contexts and is frequent
between same-sex partners. Behaviour 158: 249–276.
https://doi.org/10.1163/1568539X-bja10062

Savage-Rumbaugh ES, Wilkerson BJ 1978. Socio-sexual be-19

Pan Africa News, 28(2):17–20 (2022)

havior in Pan paniscus and Pan troglodytes: a comparative
study. J Hum Evol 7: 327–344.
https://doi.org/10.1016/S0047-2484(78)80074-8

Shefferly N, Fritz P 1992. Male chimpanzee behavior in relation to female ano-genital swelling. Am J Primatol 26:
119–131.
https://doi.org/10.1002/ajp.1350260206

Stanford C 1996. The hunting ecology of wild chimpanzees:
implications for the evolutionary ecology of Pliocene hominids. Am Anthropol 98: 96–113.
https://doi.org/10.1525/aa.1996.98.1.02a00090

Takahata Y 1982. The socio-sexual behavior of Japanesemonkeys. Z Tierpsychol 59: 89–108.
https://doi.org/10.1111/j.1439-0310.1982.tb00332.x

Woods V, Hare B 2011. Bonobo but not chimpanzee infants
use socio-sexual contact with peers. Primates 52: 111–116.
https://doi.org/10.1007/s10329-010-0229-z

Received: 21 January 2022
Accepted: 28 February 2022

20

Pan Africa News, 28(2): 21 (2022)

Letter

MWCS under COVID-19 crisis
Kazuhiko Hosaka
Mahale Wildlife Conservation Society Japan (MWCS-J)
E-mail: hosaka@kamakura-u.ac.jp

Firstly, I would like to express my deepest gratitude
to all our members for your continued support.
Founded in 1994, Mahale Wildlife Conservation
Society (MWCS) has provided a forum for researchers on
the two Pan species involved in fieldwork across Africa toshare information on research and conservation throughthe publication of Pan Africa News. Another mission ofours is to contribute to wildlife conservation in the chimpanzee habitats of western Tanzania, particularly in the
Mahale Mountains National Park.
MWCS has been engaged in three projects in Mahale.
Firstly, we have supported the park headquarters at
Bilenge to improve their facilities, for example, by donating a visitor center and creating tourist exhibits to be
displayed there. Secondly, we have promoted communitybased conservation at villages such as Katumbi outside
the park. The proactive involvement of local communities is vital for successful wildlife conservation. For thispurpose, we have prioritized the improvement of social
infrastructure, such as primary education and a dispensary in Katumbi, with the aid of the Embassy of Japan in
Tanzania. We have produced Wanyama wa Mahale, ananimal guide written for local children with a grant fromthe Toyota Foundation. Since 2009, MWCS has awarded
special scholarships to three outstanding youths who aspire to pursue higher education to contribute to their community. The third project is to enhance environmental
conservation in and around Mahale. For example, a project to control Senna spectabilis, an invasive alien plant
species, was successfully implemented in collaboration
with the National Park management. Importantly, as therisk of zoonotic infection from humans to chimpanzees
has heightened with the increase in the number of tourists, we have instructed tourism operators to take effective measures to prevent viral transmission, such as thewearing of masks during observation and maintaining anappropriate distance from the wild apes.
These activities would not have been feasible without
the assistance of research assistants belonging to the indigenous Tongwe community. Additionally, our activities
are beneficial to them in that they earn cash income byassisting us with their traditional knowledge of nature in
Mahale.
Since late March 2020, the researchers’ fieldwork has
been suspended due to the strict precautions against the
spread of COVID-19. Our research assistants have been
maintaining minimal activities inside the park, such as themaintenance of research trails and health monitoring ofM-group chimpanzees. To help them stay in the park andcontinue their activities, MWCS-J contributed 300,000
yen in December 2021. Although the short-term outlook
for our own activities is unpredictable, we are planning
to return to the field as soon as possible, while keeping aclose eye on the domestic and international developments
related to overseas travels. By August, we hope to resume
educational and medical support in Katumbi, which has
been halted for the past two years.
We would be grateful if you would consider supporting our activities under the prolonged pandemic. If
you are interested in joining MWCS or donating money,
please contact us at info@mahale.main.jp. We will theninform you of the remittance methods and other details.

21Pan Africa News, 28(2): 22 (2022)

Book Info

William C. McGrew
Chasing after Chimpanzees: The Making of aPrimatologist
Gloucestershire: Mereo Books, 298 pp.
Published in 2021
ISBN: 9781861515827, $14.00 (USA), Paperback
Having moved from zoology to psychology to anthropology on both sidesof the Atlantic, Bill McGrew developed a fascination for chimpanzees which
led to him spending four decades studying our nearest living relations in their
African homelands. He held a series of academic posts in the USA and UK,
culminating in a professorship at the University of Cambridge and ending inretirement to Scotland. As he puts it: “I was lucky enough to be paid by various
academic institutions to do what I would have paid them to let me do”. Thismemoir consists of a series of stories and vignettes from a varied and colourful life, mainly involving animals, and naturally focusing on chimpanzees. Allproceeds will go to organisations that rescue and care for chimpanzees.
CONTENTS
Preface
Chronology
EARLY DAYS
1. Big Wind
3
2. Early Gender Bending
4
3. Introduction to Chimpanzees				
5
4. Fishing and Hunting
7
5. Precocial Opportunities
9
6. Bones and Stones
11
7.		 Herps13
8. Numbers Games
16
9.		 BILGE
17
10. First Publication
20
11. Political Schemes
21
12. Seeking Curly-Tails
23
13. How to Get a Rhodes
Scholarship
24
ADULTHOOD
14. Ocean Lining
33
15. The Lord of the Rings
Himself35
16. Skiing the Iron Curtain
36
17. Front Page News38
18. Vietnam
3919. Grosvenor Square
41
20. Dylan, etc.
42
21. Football Conversion
43
22. Haunting Voices45
23. McGrew Origins
46
24. Hibs Forever48
25. Changing Addictions50
26. 26.2 Miles or 42 Kilometres				
51
27. Becoming Scottish
55
28. Coaching57
29. West Highland Way
59
30. Super Bowl Surprise61
31. Incarceration
63
32. Deer Me!
64
33. Investments Gone Awry
65

34. Horses for Courses
35. Deadly Hobby
36. Never Again!
37. Ethereal Diving
38. Travels
39. Flashbulb Memories
40. Hearty Send-off

67
68
70
71
73
75
77

ACADEMIA
41. Publish or Perish
42. Degrees of Difficulty
43. Esteemed Mentors
44. Chimpanzee Dentistry
45. Afternoon Delight
46. Ape Escapology
47. The Great Escape
48. Wenner-Gren
49. Dian and Me
50. Chimpologists and Sport
51. Munro-Bagging
52. Gummed-up Marmosets
53. Captive Cotton-tops
54. Snakebit
55. Short-term Teaching
56. Andechs
57. Ardi and Me
58. Stamped Upon
59. Chimp Haven
60. Marketing Great Apes
61. Versailles High Jinx
62. Stances with Wolves
63. Name Game
64. Miami to Cambridge
65. Flakey Acts
66. High Table
67. Grape Expectations
68. Bookmaking
69. Honorariness

81
84
86
89
91
93
95
96
99
101
103
105
108
110
111
113
116
117
118
121
124
125
126
128
130
131
135
137
140

FIELDWORK
70. Ravenglass
71. Cayo Santiago
72. Chimpology’s Scope
73. Pan Places

161
162
164
166

22

74. Habituation
171
75. Circumstantial Evidence 173
76. Transection
177
77. Shit Happens
180
78. Gimme Shelter
182
79. Real-life Altruism
186
80. Field Hazards
187
81. Unwelcome Companions 189
82. Figan’s and My Predicament
				
191
83. Tropical Fruitery
192
84. Job-hunting
194
85. Scheherazade the Hen
195
86. Customary Grooming
196
87. Sahara Crossing
198
88. Gravity Rules
201
89. Re-Wild? Release?
Rehabilitate!
202
90. Assirik Daily Life205
91. Assirik Critters
208
92. Avian Enterprise210
93. Scavenging
211
94. Wild Baking
213
95. Flying Chimpanzee
214
96. Waterhole Watcher
215
97. Revenge of the Village Dog
			218
98. Pygmies
220
99. Pirates!
223
100. Flying to the Field
224
101. Poachers
225
102. Handedness
228
103. Honey’s Costs
232
104. Indian Interlude234
105. Primate Archaeology
237106. Boa Constrictor
240107. Monkey Technology
241108. Impossible Bipedality244
109. Beyond Chimpanzees
246
110. Three Aces
247
Index

250