2025/11/22 by Dena J. Clink · 1 voice
Psychology · Medicine · Social Sciences · #Primate Behavior and Ecology #Zoonotic diseases and public health #Pleistocene-Era Hominins and Archaeology
paper · pdf · doi:10.1111/cobi.70170
openalex publication_date 2025/11/22 · openalex created_date 2025/11/23 · openalex updated_date 2026/07/28
Apes on the Edge: Chimpanzee Life on the West African Savanna. Pruetz, J. 2025. University of Chicago Press, Chicago, IL. 160 pp. US25.00 (paperback). ISBN 978-0-226-83751-2. State of the Apes: Disease, Health and Ape Conservation. White, A., S. Unwin, A. Lanjouw, K. Scholfield, and H. Rainer, editors. 2024. State of the apes. Volume 5. Cambridge University Press, Cambridge, UK. xxiv+429 pp. £29.99 (paperback). Free download from https://www.stateoftheapes.com/volume-5-disease-health-and-ape-conservation/. ISBN 978-1-009-06998-4. Anthropogenic impacts on the natural world have been far-reaching. We are facing the collapse of climate and ecological systems, along with the potential loss of millions of species (IPBES, 2019), including many threatened and endangered apes. Historically, apes and humans had limited contact; however, now more than 70% of apes live outside protected areas, which means that many of them will interact with humans in some capacity. These 2 books explore the many ways in which apes and humans interact and the complexities of these interactions. The savanna chimpanzees featured in Apes on the Edge coexist with humans in a way that is not commonly seen in the well-studied forest-dwelling chimpanzees, and State of the Apes emphasizes the importance of peaceful coexistence between humans and apes. However, ape–human interactions come with risks to both parties, including stress or harm to the animals, possible disease transmission, competition for resources, and crop raiding. Whether the shared coexistence is through scientific research, human–wildlife conflict, or in a captive setting, both books explore ways to improve outcomes for apes and the humans living alongside them. Apes on the Edge: provides an engaging and informative overview of Dr. Jill Pruetz's work on the Fongoli Savannah Chimpanzee Project in Senegal. Despite chimpanzees being some of the most well-studied mammals—researchers have accumulated more than 500 years of observer effort studying chimpanzees (p. 7)—most of this work was on forest-dwelling chimpanzees. Pruetz shows us that we still have a lot to learn, particularly about savanna-living chimpanzees. From hunting bush babies (Galago senegalensis) with sticks to using caves and watering holes to cool off in the extreme heat, Pruetz guides us through her team's unexpected discoveries about these “apes on the edge.” She consistently reminds the reader that many of these unique behaviors can be attributed to their extreme habitat. Pruetz carefully weaves storytelling about individual chimpanzees with clear explanations regarding the importance of her observations to relevant ecological theory in a way that is accessible, enjoyable, and educational all at once. As an aspiring primatologist, the first book I read was by Biruté Galdikas about her work with orangutans on Indonesian Borneo (Galdikas, 1995). Some of the field experiences that stand out in my mind years later include Galdikas wading through neck-deep peat swamp water to follow the orangutans and her account of spending many days incapacitated due to the mistake of sitting on a log that released skin-burning sap. I was truly inspired by Galdikas’ dedication to her primate subjects. My more recent reading of Apes on the Edge brought about similar emotions. Pruetz documents working in the harsh savanna environment, where the heat index can get over 49°C (120°F) during the early part of the rainy season, but she emphasizes that this is one of the best times to observe the chimpanzees because they tend to range together as a single, large group. Fongoli chimpanzees engage in beehive raids in a region where bees are highly aggressive, easily roused, and and encounters often lead to fatal stings. Pruetz now carries injectable epinephrine with her in the field due to her sensitivity to bee stings (p. 90). Apes on the Edge provides an enchanting overview of Pruetz's life as a field primatologist, and I am confident that this book will join the ranks of the works of Jane Goodall, Dian Fossey, and Biruté Galdikas to inspire the next generations of field primatologists. I particularly enjoyed the personal aspects of Pruetz's story, including the challenges that come with working in another country and different culture. I also appreciated her emphasis on the invaluable expertise of locals (p. 13). Pruetz shares that her career trajectory, like that of many field ecologists and primatologists, has led her to spend less time in the field and more time fundraising for the long-term sustainability of the project. It is clear that the efforts and resources put into training and supporting her local team to be self-sufficient facilitated much of this transition. State of the Apes: Disease, Health and Ape Conservation provides a comprehensive overview of ape disease and health and the relevance of these topics to ape conservation. In reading State of the Apes, we see that human health and the health of nonhuman apes, including gibbons, orangutans, gorillas, chimpanzees, and bonobos, are intricately intertwined due to shared evolutionary history, similar susceptibility to disease, and overlapping use of habitats and resources. The book provides a balanced and nuanced discussion of a diverse range of topics, including the One Health paradigm as it relates to ape health and conservation, the costs and benefits of ape tourism and habituation, and a discussion of ape health and ethics. It covers topics important for all ape researchers, even if their research does not specifically focus on disease or health, particularly topics related to ethics, habituation, and interventions. The list of best practices to minimize the risk of disease transmission from people to apes (p. 99) is very useful. Requirements for successful snare removal and snaring's individual, environmental, and social factors are discussed (p. 153). The case studies included throughout add great value, in particular those in the One Health chapter, which highlights the important work of nongovernmental organizations (NGOs) across ape range countries and is organized in the context of the ethical framework of the Berlin Principles of One Health (Gruetzmacher et al., 2021). The intended audience includes policy makers, industry experts, decision makers, academics, researchers, and NGOs. That the entire volume is available online for free is an important step in making this information accessible to practitioners in countries where apes are found. Translated versions are also available in other languages, including Bahasa Indonesia, Chinese (Mandarin), and French. In addition to the chapters focused on ape disease and health, there is a separate section on the status of apes in the wild and captivity that includes a summary of the number of apes in captivity worldwide and an online-only appendix that summarizes global ape abundance estimates at the site level. I commend the editors and authors for their efforts to make this information widely and freely accessible and for their coordinated efforts in compiling all the current information on the status of the apes. Both books emphasize the interconnectedness of human and ape health. Pruetz often frames her work in the One Health paradigm, although she does not explicitly use the term, and it is a major focus of State of the Apes. Pruetz emphasizes that the problems the Fongoli chimpanzees face are the same for the humans living alongside them (p. 118). For example, access to clean water limits where chimpanzees can go and what they can eat during the dry season; access to clean drinking water is also something rural people in the area lack. Long-standing cultural taboos against hunting and eating chimpanzees (p. 119) mean that local people have been instrumental in the conservation of these apes. Pruetz writes that improving health for people in the area indirectly affects chimpanzee health by maintaining a positive relationship between people and chimpanzees and reduces the likelihood of disease transmission (p. 120). State of the Apes also notes that “ape survival is inextricably linked to human development (p. 75),” highlighting converging viewpoints regarding the importance of a conservation approach that integrates needs of local communities and apes in their natural habitat. Compassionate conservation, which is discussed in State of the Apes, proposes conservation should recognize the value and the importance of the well-being of individual animals, not just their value relative to populations or species (Bekoff, 2010; Ramp & Bekoff, 2015). Compassionate conservation is a topic of ongoing intellectual and practical debate, but the authors posit that it is a useful framework for navigating the complexities of the health and well-being of individual apes in the context of conservation (p. 149). Apes on the Edge provides a complementary viewpoint to compassionate conservation and includes many engaging stories about individual chimpanzees. One of my favorites is that of the adult male Bo who would shake a branch every time Pruetz approached a tree with a snake in it. When Pruetz got too close, Bo jumped out of the tree and ran away, looking back at Pruetz and urging her to follow, a common chimpanzee behavior. Her accounts of Fongoli chimpanzee behavior make it easy to see and appreciate savannah chimpanzees as individuals and provide important case studies that can inform the compassionate conservation debate. Pruetz does a fantastic job of sharing the challenges surrounding establishment of the project and centers much of the discussion around important ethical considerations. Getting initial funding for the project was difficult because reviewers thought savanna chimpanzees could not be habituated, given that previous habituation efforts with other savannah chimpanzees were abandoned because it was too difficult. Pruetz and her team succeeded, however. After only 4 years of habituation efforts, they were able to follow them for a full day, night-nest to night-nest. Pruetz initially wanted to focus on female chimpanzees and how they deal with the relatively harsh environment of the savanna. However, after learning that female chimpanzees may be targeted by poachers so that their infants can be taken for the pet trade, Pruetz decided to focus habituation efforts on male chimpanzees. Fongoli chimpanzees are habituated only to small teams of observers, so they are not susceptible to disease transmission or potential poaching, which can happen with overhabituation. While reading Apes on the Edge in tandem with State of the Apes, some aspects jumped out in a way that perhaps would not have otherwise. For example, Pruetz describes an arduous journey from the United States to Senegal in response to a chimpanzee infant being taken from its mother by hunters. Pruetz held the infant shortly after arrival so that the project manager could administer eye drops (p. 100). Although Pruetz mentioned she wore a surgical mask and used hand sanitizer, guidance from State of the Apes suggests that international travel and close and repeated contact with apes leads to a high risk of disease transmission and suggests a quarantine time of 7 days. As mentioned above, Pruetz discusses the ethical issues regarding habituation. However, in light of the very long process of habituating the Fongoli chimpanzees, the potential impacts of stress related to habituation highlighted in State of the Apes could have been discussed more in depth, particularly given that Fongoli chimpanzees already live in a harsh environment. These 2 books provide a complimentary, in-depth look at what it means for us as humans to coexist with our ape relatives. Both emphasize the need for safeguarding the health and well-being of individual apes and that of their human neighbors. I see both as calls to action for all primatologists, including myself, to explore and consider all the ethical and moral implications of their scientific and conservation work. We should all work to center the general principles of compassionate conservation, including the principles of doing no harm, valuing the individual, and working toward a peaceful coexistence between humans and apes.