Comparing Predictors and Outcomes of Higher Allostatic Load across Zoo-Housed African Great Apes
Stressors over the lifespan can contribute to physiological dysregulation, or allostatic load. Allostatic load has been studied in humans using allostatic load indices (ALIs) for over 25 years, but the same methods are rarely applied to other species. We constructed an ALI for zoo-housed western lowland gorillas, chimpanzees, and bonobos and tested potential predictors of […]
Not lost in translation: Changes in social dynamics in Bonobos after colony relocation and fusion with another group
Animal welfare is affected by both physical and social environment and these aspects can be particularly critical for cognitively and socially-complex species, such as great apes. We observed a captive group of nine bonobos before (April-June 2021) and after relocation (June-August 2022) and we checked whether and to what extent the transfer would affect their […]
Blood pressure monitoring in zoologically managed bonobos (Pan paniscus)
In response to the growing evidence that hypertension may play a significant role in the development of cardiovascular disease (CVD) in bonobos, the Great Ape Heart Project established a finger blood pressure (BP) monitoring protocol for zoo-housed bonobos. The ability to monitor BP without the use of anesthesia provides more opportunities to detect potential hypertension […]
Investigating the effects of sex and rearing-history on social network position in zoo-housed bonobos
Social network analysis can be a valuable tool for the management of zoo-housed animals and captive breeding programs, since an individual’s social network position is typically associated with its reproductive success, longevity, and overall welfare. This is especially true for primates, due to their rich and complex social lives. While many studies have investigated individual […]
Time-lag of urinary and salivary cortisol response after a psychological stressor in bonobos (Pan paniscus)
Cortisol is often measured as a marker for stress. Therefore, a profound validation of the time-lag between the stressor and the increase and peak in cortisol levels is needed. No study measured both the urinary and salivary cortisol time-lag after a psychological stressor. In this study, we used a frequent sampling study design to (1) […]
Welfare of Apes in Captive Environments: Comments On, and By, a Specific Group of Apes
Accurately determining the proper captive environment for apes requires adequately assessing the psychological similarities between apes and humans. Scientists currently believe apes lack mental complexity (Millikan, 2006), raising questions concerning the evolution of human culture from ape-like societies (Tomasello, 1999) .A long-term cultural study with bonobos suggests less intellectual divergence from humans than currently postulated […]
Token transfers among great apes (Gorilla gorilla, Pongo pygmaeus, Pan paniscus, and Pan troglodytes): Species differences, gestural requests, and reciprocal exchange
Great apes appear to be the nonhuman primates most capable of recognizing trading opportunities and engaging in transfers of commodities with conspecifics. Spontaneous exchange of goods between them has not yet been reported. We tested gorillas (Gorilla gorilla), orangutans (Pongo pygmaeus), bonobos (Pan paniscus), and chimpanzees (Pan troglodytes) in a token-exchange task involving two conspecifics […]
Inferences About the Location of Food in the Great Apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus)
Bonobos (Pan paniscus; n 4), chimpanzees (Pan troglodytes; n 12), gorillas (Gorilla gorilla; n 8), and orangutans (Pongo pygmaeus; n 6) were presented with 2 cups (1 baited) and given visual or auditory information about their contents. Visual information consisted of letting subjects look inside the cups. Auditory information consisted of shaking the cup so […]
Piagetian Liquid Conservation in the Great Apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus)
An understanding of Piagetian liquid conservation was investigated in 4 bonobos (Pan paniscus), 5 chimpanzees (Pan troglodytes), and 5 orangutans (Pongo pygmaeus). The apes were tested in the ability to track the larger of 2 quantities of juice that had undergone various kinds of transformations. The accuracy of the apes’ judgment depended on the shape […]
Searching in the Middle—Capuchins’ (Cebus apella) and Bonobos’ (Pan paniscus) Behavior During a Spatial Search Task
In this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. Five bonobos (Pan paniscus) and 2 capuchin monkeys (Cebus apella) were tested in a series of experiments with the expansion test paradigm. The primates were trained to search in the […]