Article
Agriculture, Dairy & Animal Science
Amy Fultz, Akie Yanagi, Sarah Breaux, Leilani Beaupre
Summary: This study examines how group size, location, rearing, age, and sex differences affect affiliative, aggressive, and submissive behaviors in chimpanzees during social integrations. The results show that the chimpanzees' sex, location, and group size are associated with the frequency of affiliative behaviors during social integration. All variables except group size are associated with the frequency of aggressive behavior. The frequency of submissive behavior differs based on the chimpanzees' sex, rearing history, and group size.
Article
Multidisciplinary Sciences
Claudia Wilke, Nicole J. Lahiff, Kris H. Sabbi, David P. Watts, Simon W. Townsend, Katie E. Slocombe
Summary: This article examines the differences between humans and great apes in their ability to share attention with others about external entities. By observing a wild chimpanzee showing an item of interest to a conspecific, the researchers suggest that in specific social conditions, wild chimpanzees may use referential showing gestures like humans, indicating a quantitative rather than qualitative difference between humans and our closest living relatives.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Psychology, Multidisciplinary
William D. D. Hopkins, Michele M. M. Mulholland, Mary Catherine Mareno, Sarah J. Neal Webb, Steven J. J. Schapiro
Summary: Declarative and imperative joint attention are crucial developmental milestones in human infants, with implications for language development. While chimpanzees as a group perform better than chance in receptive joint attention tasks, individual performance did not show significant differences. The performance in object choice tasks was not significantly heritable, and there were no significant effects of sex, rearing history, or colony, suggesting a complex interplay of factors influencing task performance. The differences in gray matter covariation between those who passed and failed the task suggest potential implications for the importance of social brain networks in both human and nonhuman primate social cognition.
FRONTIERS IN PSYCHOLOGY
(2022)
Article
Agriculture, Dairy & Animal Science
Sarah Neal Webb, Steven Schapiro
Summary: The relationship between locomotion and welfare in captive chimpanzees is complex, but increased locomotion is generally considered to indicate improved welfare. However, there is a limited number of studies that have used locomotion as a welfare indicator. Four previously published studies showed that increased locomotion in captive chimpanzees is associated with enhanced welfare, suggesting that time spent in locomotion can be used as a sensitive measure of welfare.
Article
Zoology
Kristin Havercamp, Naruki Morimura, Satoshi Hirata
Summary: The study revealed that as chimpanzees age, they experience more frequent awakenings and shorter sleep bouts, resulting in more fragmented sleep. However, nightly sleep duration and the length of awake bouts did not differ significantly between different study periods.
INTERNATIONAL JOURNAL OF PRIMATOLOGY
(2021)
Article
Multidisciplinary Sciences
Rafaela S. C. Takeshita, Melissa K. Edler, Richard S. Meindl, Chet C. Sherwood, William D. Hopkins, Mary Ann Raghanti
Summary: This study investigated the relationship between DHEAS levels and age, as well as the potential associations between the DHEAS/cortisol ratio and cognitive function in chimpanzees. The results showed that DHEAS levels declined with age and the DHEAS/cortisol ratio was positively correlated with spatial cognition.
Article
Neurosciences
William D. Hopkins, Oliver Coulon, Adrien Meguerditchian, Nicky Staes, Chet C. Sherwood, Steven J. Schapiro, Jean-Francois Mangin, Brenda Bradley
Summary: This study examined the role of genetic factors in individual variation in superior temporal sulcus (STS) morphology in chimpanzees. The results showed significant correlations between single nucleotide polymorphisms in the KIAA0319 and AVPR1A genes and STS depth and lateralization, but no significant effects on surface area and depth measures for the central sulcus. The overall findings suggest that genetic factors contribute to a small to moderate amount of variation in STS morphology in chimpanzees.
Article
Multidisciplinary Sciences
Adrienne B. Chitayat, Serge A. Wich, Matthew Lewis, Fiona A. Stewart, Alex K. Piel
Summary: Understanding the ecological factors affecting chimpanzee density in Mahale Mountains National Park is crucial for conservation efforts, with nest density being linked to food and nesting tree availability, topographic features, and the diversity of feeding tree species. This study provides valuable baseline data for monitoring and protecting this endangered species in Tanzania.
Article
Ecology
Cassandra K. Bugir, Thomas M. Butynski, Matt W. Hayward
Summary: The common chimpanzee is the closest living relative of modern humans, and research has shown that they are not just herbivorous, but also use various techniques to hunt a variety of prey species. Their prey preferences are influenced by the sex ratio within chimpanzee groups. Studying chimpanzee hunting behavior and diet can provide valuable information for conservation management and contribute to a better understanding of the evolution of human hunting behavior.
ECOLOGY AND EVOLUTION
(2021)
Article
Zoology
Luc Roscelin Dongmo Tedonzong, Maxwell Bienvenu Mfula Ndju'u, Martin Tchamba, Tsi Evaristus Angwafo, Luc Lens, Nikki Tagg, Jacob Willie
Summary: Sleep is vital for great apes, who build sleeping platforms every night. In a community of chimpanzees, each subgroup chooses a sleeping site where individuals construct sleeping platforms, mostly on trees. This study reveals that chimpanzees prefer trees with a diameter of 40-50 cm for sleeping and build platforms at a height of 16 m. The vegetation structure plays a crucial role in the selection of sleeping sites by chimpanzees.
AMERICAN JOURNAL OF PRIMATOLOGY
(2023)
Article
Agriculture, Dairy & Animal Science
Julia L. Greeson, Kara Gabriel, J. B. Mulcahy, Bonnie King Hendrickson, Susan D. Lonborg, Jay C. Holloway
Summary: Environmental enrichment is important for captive chimpanzees to minimize stress and boredom and provide opportunities for species-typical behaviors. This study investigated the associations between enrichment objects, manipulation behaviors, and social contexts in captive chimpanzees. It also examined the individual differences in enrichment object preferences. The results showed that enrichment objects might serve distinct social and behavioral purposes, and chimpanzees vary in their enrichment object preferences. Caregivers should consider individual needs when providing enrichment to improve chimpanzees' experiences in captivity.
Article
Agriculture, Dairy & Animal Science
Andrea W. Clay, Stephen R. Ross, Susan Lambeth, Maribel Vazquez, Sarah Breaux, Rhonda Pietsch, Amy Fultz, Michael Lammey, Sarah L. Jacobson, Jaine E. Perlman, Mollie A. Bloomsmith
Summary: This study investigated the behavioral profiles of 1122 chimpanzees and found that the presence of species-typical behaviors (STBs) varied among different behaviors, with tool-use being the most common (94.3%) and nest-building being the least common (58.9%). Male chimpanzees not reared by their conspecific mother were more likely to have deficits in STBs, while female chimpanzees that were mother-reared were generally more likely to engage in STBs.
Article
Multidisciplinary Sciences
Judy Che-Castaldo, Kristin Havercamp, Koshiro Watanuki, Tetsuro Matsuzawa, Satoshi Hirata, Stephen R. Ross
Summary: This study presents a comparative analysis of life history data for chimpanzee populations in North America and Japan, revealing differences in survival patterns based on sex and region. Males generally exhibit higher mortality rates compared to females, with variation observed in first year mortality rates across different populations.
Article
Biology
Rachna B. Reddy, Kevin E. Langergraber, Aaron A. Sandel, Linda Vigilant, John C. Mitani
Summary: This study investigated adolescent and young adult male chimpanzees at Ngogo in Uganda, finding that socially immature adolescent males father offspring by mating with nulliparous females. Mating success was influenced by affiliative bonds and aggression, with male aggression towards females becoming more important as they aged, especially towards females with whom they shared affiliative bonds. These results parallel patterns of sexual coercion in humans, particularly within close affiliative relationships.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2021)
Article
Neurosciences
M. M. Mulholland, S. J. Schapiro, C. C. Sherwood, W. D. Hopkins
Summary: Humans and chimpanzees both exhibit tool use skills, suggesting a common ancestor for this ability. Research shows a genetic and phenotypic association between tool use abilities and specific brain regions in chimpanzees.
Article
Behavioral Sciences
Rachna B. Reddy, Christopher Krupenye, Evan L. MacLean, Brian Hare
Article
Immunology
Jacob D. Negrey, Rachna B. Reddy, Erik J. Scully, Sarah Phillips-Garcia, Leah A. Owens, Kevin E. Langergraber, John C. Mitani, Melissa Emery Thompson, Richard W. Wrangham, Martin N. Muller, Emily Otali, Zarin Machanda, David Hyeroba, Kristine A. Grindle, Tressa E. Pappas, Ann C. Palmenberg, James E. Gern, Tony L. Goldberg
EMERGING MICROBES & INFECTIONS
(2019)
Article
Zoology
Rachna B. Reddy, John C. Mitani
Article
Behavioral Sciences
Rachna B. Reddy, Aaron A. Sandel
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY
(2020)
Article
Biology
Rachna B. Reddy, Kevin E. Langergraber, Aaron A. Sandel, Linda Vigilant, John C. Mitani
Summary: This study investigated adolescent and young adult male chimpanzees at Ngogo in Uganda, finding that socially immature adolescent males father offspring by mating with nulliparous females. Mating success was influenced by affiliative bonds and aggression, with male aggression towards females becoming more important as they aged, especially towards females with whom they shared affiliative bonds. These results parallel patterns of sexual coercion in humans, particularly within close affiliative relationships.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2021)
Article
Zoology
Jacob D. Negrey, John C. Mitani, Richard W. Wrangham, Emily Otali, Rachna B. Reddy, Tressa E. Pappas, Kristine A. Grindle, James E. Gern, Zarin P. Machanda, Martin N. Muller, Kevin E. Langergraber, Melissa Emery Thompson, Tony L. Goldberg
Summary: This study reveals the relationship between viral infection and ill health in wild chimpanzees during non-outbreak periods. The total viral load is higher in ill individuals compared to healthy individuals, and male chimpanzees exhibit higher infection rates and total viral loads as they age. The findings support the hypothesis that nonlethal viral infections contribute to senescence in chimpanzees.
AMERICAN JOURNAL OF PRIMATOLOGY
(2022)