<From the Field Site>
Published online (Oct 24, 2018)
40 years of research at the Taï Chimpanzee Project
Roman M. Wittig1,2,3
1 Director, Taï Chimpanzee Project
2 Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
3 Centre Suisse de Recherches Scientifiques, Abidjan, Côte d’Ivoire
Almost 40 years ago, in the summer of 1979, Christophe and Hedwige Boesch arrived in Taï National Park, Côte d’Ivoire, to start the first chimpanzee long-term field site observing wild chimpanzees living in a primary rain forest. Christophe and Hedwige had chosen to study the chimpanzees in Taï, motivated by rumours that these chimpanzees would use hammers to pound nuts—a tool use not known in chimpanzees—and to provide data for a meaningful comparison with the savannah-woodland dwelling chimpanzees of Gombe and Mahale (Boesch & Boesch 1994).
After setting camp in the area of the UNESCO Man and the Biosphere Programme (Figure 1), they started to follow the chimpanzees and tried to habituate them without the aid of provisioning. Quickly they realised that the black shadows, they met occasionally in the forest, would dodge them again and again. After endless and unsuccessful attempts to come close to the chimpanzees and observe their behaviour, they decided to change their tactic and announce their arrival to the chimpanzees by tongue-clacking, in the hope the chimpanzees would look at them before disappearing and as such getting accustomed to the presence of the observers. Although there was no immediate improvement, by 1982 Christophe and Hedwige were able to have some direct observations. It took them, however, another two years, before the first individuals had enough trust to accept their presence even when resting. The year of 1985 marks the beginning of data collection in the first community of Taï chimpanzees, the North group (Boesch & Boesch-Achermann 2000).
Figure 1. North Camp of the Taï Chimpanzee Project in 2018 in the middle of the National Park. This is the original camp Christophe and Hedwige Boesch were living with their family until the 1990s (photo courtesy of Tokyo Broadcasting Station).
The first years of the Taï Chimpanzee Project, Christophe and Hedwige focused on the nut-cracking behaviour and the hunting behaviour. Very quickly they observed that the chimpanzees in Taï would use wooden and stone hammers, depending on the hardness of the nut shell, cracking at least five different types of nuts (Boesch & Boesch 1982, 1984). These observations were pioneering for the work on chimpanzee cultures that started at a later point in time (Whiten et al. 1999). At the same time Christophe realised that yet another behaviour, thought to be prominently involved in human evolution, was common in the Taï chimpanzees: cooperative hunting for monkeys (Boesch & Boesch 1989; Boesch 2002).
Starting in the late 1980s, Christophe and Hedwige were joined by field assistants from the villages close by to help them observing the behaviour of the chimpanzees. Gregoire Nohon and Honora Kphazi were the first ones to follow chimpanzees and became the role models for many young people from the villages, who came to the Taï Chimpanzee Project to work. With these two, the long-term data collection of behavioural focal observations started in the early 1990s.
When Christophe Boesch became director of the newly founded Max Planck Institute for Evolutionary Anthropology (MPI EVA) in 1997, the heydays of the Project started. Project staff habituated three additional neighbouring communities: South and Middle group were finally habituated in 1997 and 1998 respectively, and in East group staff started to collect behavioural data starting in 2007. Students from the MPI EVA came to Taï and investigated wide ranges of topics in behavioural ecology related to conflict (Wittig & Boesch 2003, 2010), communication (Crockford & Boesch 2003; Herbinger et al. 2009), cognition (Normand et al. 2009; Sirianni et al. 2015), competition (Anderson et al. 2002; Deschner et al. 2004; Stumpf & Boesch 2005), cooperation (Gomes & Boesch 2009, 2011), culture (Luncz et al. 2012), conservation (Campbell et al. 2008) and many other topics. At the same time the Taï Chimpanzee Project also hosted international researchers from outside the MPI, adding expertise to the project (e.g., archaeological techniques (Mercader et al. 2002), anatomical expertise (Zihlman et al. 2004)).
The Taï Chimpanzee Project, however, also suffered setbacks. The chimpanzee population had to cope with extensive individual losses due to zoonotic diseases transmission from human respiratory viruses (Köndgen et al. 2008). Only after rigorous quarantine and hygiene rules with strict reinforcement in the years 2010–2012, respiratory disease transmission was stopped (Grützmacher et al. 2017) and the population started slowly to recover. A veterinary program led by Fabian Leendertz of the Robert Koch Institute in Berlin (Germany) guarantees the constant presence of a qualified veterinarian in the field. This program, apart from its crucial contribution to the chimpanzee health, has also discovered a wide range of pathogens with formerly unknown effects on chimpanzee (e.g., Hoffmann et al. 2017).
Planning for his retirement, Christophe Boesch handed over responsibility for the Taï Chimpanzee Project to Roman Wittig and Catherine Crockford in 2013. Since then staff members habituated a sympatric living sooty mangabey group, in order to compare the socio-ecology and cognition of both species (Mielke et al. 2017, 2018), and started to habituate the fifth community of chimpanzees in the Northeast of the research area, allowing us to better observe intergroup encounters (Samuni et al. 2017). With Cathy and Roman leading the project, research took new direction using supporting hormonal measures (Samuni et al. 2018; Preis et al. 2018), experimental work (Crockford et al. 2017; Sirianni et al. 2018) and additional comparative set-ups with other species (Surbeck et al. 2017a,b).
The Taï Chimpanzee Project will celebrate 40 years of research with an international scientific symposium held 29–31 May 2019 at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. During the year 2019 a book looking back at 40 years of research in Taï will be published by Cambridge University Press.
Anderson DP, Nordheim EV, Boesch C, Moermond TC 2002. Factors influencing fission-fusion grouping in chimpanzees in the Taï National Park, Côte d’Ivoire. In: Behavioural Diversity in Chimpanzees and Bonobos. Boesch C, Hohmann G, Marchant LF (eds), Cambridge University Press, Cambridge, pp. 90–101.
Boesch C 2002. Cooperative hunting roles among Taï chimpanzees. Hum Nat 13: 27–46. https://doi.org/10.1007/s12110-002-1013-6
Boesch C, Boesch H 1982. Optimisation of nut-cracking with natural hammers by wild chimpanzees. Behaviour 83: 265–286. https://doi.org/10.1163/156853983X00192
Boesch C, Boesch H 1984. Possible causes of sex differences in the use of natural hammers by wild chimpanzees. J Hum Evol 13: 415–440. https://doi.org/10.1016/S0047-2484(84)80055-X
Boesch C, Boesch H 1989. Hunting behavior of wild chimpanzees in the Taï National Park. Am J Phys Anthropol 78: 547–573. https://doi.org/10.1002/ajpa.1330780410
Boesch C, Boesch H 1994. The Tai Chimpanzee Project in Cote d’Ivoire, West Africa. Pan Afr News 1: 5–7. https://doi.org/10.5134/143537
Boesch C, Boesch-Achermann H 2000. The Chimpanzees of the Taï Forest: Behavioural Ecology and Evolution. Oxford University Press, Oxford.
Campbell G, Kuehl H, N’Goran PK, Boesch C 2008. Alarming decline of West African chimpanzees in Côte d’Ivoire. Curr Biol 18: R903–R904. https://doi.org/10.1016/j.cub.2008.08.015
Crockford C, Boesch C 2003. Context-specific calls in wild chimpanzees, Pan troglodytes verus: Analysis of barks. Anim Behav 66: 115–125. https://doi.org/10.1006/anbe.2003.2166
Crockford C, Wittig RM, Zuberbühler K 2017. Vocalizing in chimpanzees is influenced by social-cognitive processes. Sci Adv 3: e1701742. https://doi.org/10.1126/sciadv.1701742
Deschner T, Heistermann M, Hodges K, Boesch C 2004. Female sexual swelling size, timing of ovulation, and male behavior in wild West African chimpanzees. Horm Behav 46: 204–215. https://doi.org/10.1016/j.yhbeh.2004.03.013
Gomes CM, Boesch C 2009. Wild chimpanzees exchange meat for sex on a long-term basis. PLOS One 4: e5116. https://doi.org/10.1371/journal.pone.0005116
Gomes CM, Boesch C 2011. Reciprocity and trades in wild West African chimpanzees. Behav Ecol Sociobiol 65: 2183–2196. https://doi.org/10.1007/s00265-011-1227-x
Grützmacher K, Keil V, Leinert V et al. 2017. Human quarantine: Toward reducing infectious pressure on chimpanzees at the Taï Chimpanzee Project, Côte d’Ivoire. Am J Primatol 80: e22619. https://doi.org/10.1002/ajp.22619
Herbinger I, Papworth S, Boesch C, Zuberbühler K 2009. Vocal, gestural and locomotor responses of wild chimpanzees to familiar and unfamiliar intruders: A playback study. Anim Behav 78: 1389–1396. https://doi.org/10.1016/j.anbehav.2009.09.010
Hoffmann C, Zimmermann F, Biek R et al. 2017. Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest. Nature 548: 82–86. https://doi.org/10.1038/nature23309
Köndgen S, Kühl H, N’Goran PK et al. 2008. Pandemic human viruses cause decline of endangered great apes. Curr Biol 18: 260–264. https://doi.org/10.1016/j.cub.2008.01.012
Luncz LV, Mundry R, Boesch C 2012. Evidence for cultural differences between neighboring chimpanzee communities. Curr Biol 22: 922–926. https://doi.org/10.1016/j.cub.2012.03.031
Mercader J, Panger M, Boesch C 2002. Excavation of a chimpanzee stone tool site in the African rainforest. Science 296: 1452–1455. https://doi.org/10.1126/science.1070268
Mielke A, Preis A, Samuni L et al. 2018. Flexible decision-making in grooming partner choice in sooty mangabeys and chimpanzees. Roy Soc Open Sci 5: 172143. https://doi.org/10.1098/rsos.172143
Mielke A, Samuni L, Preis A et al. 2017. Bystanders intervene to impede grooming in western chimpanzees and sooty mangabeys. Roy Soc Open Sci 5: 171296. https://doi.org/10.1098/rsos.171296
Normand E, Ban SD, Boesch C 2009. Forest chimpanzees (Pan troglodytes verus) remember the location of numerous fruit trees. Animal Cogn 12: 797–807. https://doi.org/10.1007/s10071-009-0239-7
Preis A, Samuni L, Mielke A et al. 2018. Urinary oxytocin levels in relation to post-conflict affiliations in wild male chimpanzees (Pan troglodytes verus). Horm Behav 105: 28–40. https://doi.org/10.1016/j.yhbeh.2018.07.009
Samuni L, Preis A, Deschner T, Crockford C, Wittig RM 2018. Reward of labor coordination and hunting success in wild chimpanzees. Comm Biol 1: 138. https://doi.org/10.1038/s42003-018-0142-3
Samuni L, Preis A, Mundry R et al. 2017. Oxytocin reactivity during intergroup conflict in wild chimpanzees. PNAS 114: 268–273. https://doi.org/10.1073/pnas.1616812114
Sirianni G, Mundry R, Boesch C 2015. When to choose which tool: Multidimensional and conditional selection of nut-cracking hammers in wild chimpanzees. Anim Behav 100: 152–165. https://doi.org/10.1016/j.anbehav.2014.11.022
Sirianni G, Wittig RM, Gratton P et al. 2018. Do chimpanzees anticipate an object’s weight? A field experiment on the kinematics of hammer-lifting movements in the nut-cracking Taï chimpanzees. Animal Cogn 21: 109–118. https://doi.org/10.1007/s10071-017-1144-0
Stumpf RM, Boesch C 2005. Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Taï National Park, Côte d’Ivoire. Behav Ecol Sociobiol 57: 511–524. https://doi.org/10.1007/s00265-004-0868-4
Surbeck M, Boesch C, Girard-Buttoz C et al. 2017a. Comparison of male conflict behavior in chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), with specific regard to coalition and post-conflict behavior. Am J Primatol 79: e22641. https://doi.org/10.1002/ajp.22641
Surbeck M, Girard-Buttoz C, Boesch C et al. 2017b. Sex-specific association patterns in bonobos and chimpanzees reflect species differences in cooperation. Roy Soc Open Sci 4: 161081. https://doi.org/10.1098/rsos.161081
Whiten AJ, Goodall J, McGrew WC et al. 1999. Cultures in chimpanzees. Nature 399: 682–685. https://doi.org/10.1038/21415
Wittig RM, Boesch C 2003. “Decision-making” in conflicts of wild chimpanzees (Pan troglodytes): An extension of the relational model. Behav Ecol Sociobiol 54: 491–504. https://doi.org/10.1007/s00265-003-0654-8
Wittig RM, Boesch C. 2010. Receiving post-conflict affiliation from the enemy’s friend reconciles former opponents. PLOS One 5: e13995. https://doi.org/10.1371/journal.pone.0013995
Zihlman A, Bolter D, Boesch C 2004. Wild chimpanzee dentition and its implications for assessing life history in immature hominin fossils. PNAS 101: 10541–10543. https://doi.org/10.1073/pnas.0402635101
Received: 14 September 2018
Accepted: 20 October 2018
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