Yumi Yamanashi

Tools to tipple: ethanol ingestion by wild chimpanzees using leaf-sponges

African apes and humans share a genetic mutation that enables them to effectively metabolize ethanol. However, voluntary ethanol consumption in this evolutionary radiation is documented only in modern humans. Here, we report evidence of the long-term and recurrent ingestion of ethanol from the raffia palm (Raphia hookeri, Arecaceae) by wild chimpanzees (Pan troglodytes verus) at Bossou in Guinea, West Africa, from 1995 to 2012. Chimpanzees at Bossou ingest this alcoholic beverage, often in large quantities, despite an average presence of ethanol of 3.1% alcohol by volume (ABV) and up to 6.9% ABV. Local people tap raffia palms and the sap collects in plastic containers, and chimpanzees use elementary technology—a leafy tool—to obtain this fermenting sap. These data show that ethanol does not act as a deterrent to feeding in this community of wild apes, supporting the idea that the last common ancestor of living African apes and modern humans was not averse to ingesting foods containing ethanol.

Effects of Relocation and Individual and Environmental Factors on the Long-Term Stress Levels in Captive Chimpanzees (Pan troglodytes): Monitoring Hair Cortisol and Behaviors.

Understanding the factors associated with the long-term stress levels of captive animals is important from the view of animal welfare. In this study, we investigated the effects of relocation in addition to individual and environmental factors related to social management on long-term stress level in group-living captive chimpanzees by examining behaviors and hair cortisol (HC). Specifically, we conducted two studies. The first compared changes in HC levels before and after the relocation of 8 chimpanzees (Study 1) and the second examined the relationship between individual and environmental factors and individual HC levels in 58 chimpanzees living in Kumamoto Sanctuary (KS), Kyoto University (Study 2). We hypothesized that relocation, social situation, sex, and early rearing conditions, would affect the HC levels of captive chimpanzees. We cut arm hair from chimpanzees and extracted and assayed cortisol with an enzyme immunoassay. Aggressive behaviors were recorded ad libitum by keepers using a daily behavior monitoring sheet developed for this study. The results of Study 1 indicate that HC levels increased during the first year after relocation to the new environment and then decreased during the second year. We observed individual differences in reactions to relocation and hypothesized that social factors may mediate these changes. In Study 2, we found that the standardized rate of receiving aggression, rearing history, sex, and group formation had a significant influence on mean HC levels. Relocation status was not a significant factor, but mean HC level was positively correlated with the rate of receiving aggression. Mean HC levels were higher in males than in females, and the association between aggressive interactions and HC levels differed by sex. These results suggest that, although relocation can affect long-term stress level, individuals’ experiences of aggression and sex may be more important contributors to long-term stress than relocation alone.

Analysis of hair cortisol levels in captive chimpanzees: Effect of various methods on cortisol stability and variability

Graphical abstract Summary of the experimental process. The items colored blue affected the results of the hair cortisol analysis in the present study. The stippled items were found to affect the results obtained in our previous study [1].

Common marmoset ( Callithrix jacchus ) personality, subjective well-being, hair cortisol level and AVPR1a , OPRM1 , and DAT genotypes

We studied personality, subjective well-being, and hair cortisol level, in common marmosets Callithrix jacchus, a small, cooperatively breeding New World monkey, by examining their associations with one another and genotypes. Subjects were 68 males and 9 females that lived in the RIKEN Center for Life Science Technologies. Personality and subjective well-being were assessed by keeper ratings on two questionnaires, hair samples were obtained to assay cortisol level and buccal swabs were used to assess AVPR1a, OPRM1 and DAT genotypes. Three personality domains—Dominance, Sociability, and Neuroticism—were identified. Consistent with findings in other species, Sociability and Neuroticism were related to higher and lower subjective well-being, respectively. Sociability was also associated with higher hair cortisol levels. The personality domains and hair cortisol levels were heritable and associated with genotypes: the short form of AVPR1a was associated with lower Neuroticism and the AA genotype of the A111T SNP of OPRM1 was related to lower Dominance, lower Neuroticism, and higher hair cortisol level. Some genetic associations were not in directions that one would expect given findings in other species. These findings provide insights into the proximate and ultimate bases of personality in common marmosets, other primates and humans.

Is Hair Cortisol Useful for Animal Welfare Assessment? Review of Studies in Captive Chimpanzees

Appleby & Hughes, 1997). Various methodologies exist to assess animal welfare status, includThe objective assessment of animal welfare is ing the monitoring of behavior and measurement of important for building consensus among people physiological parameters related to health and emoconcerned with animals and for advancing our tional states (Fraser, 2008). Among these, a major understanding of animals in our care. The analysis approach is the analysis of physiological stress of physiological stress response using glucocorresponse using glucocorticoids, the levels of which ticoids is one of the major approaches for animal often increase when animals face a stressor and welfare assessment. Recently, cortisol accumulated which are known to affect animal health in several in hair or other keratinous materials of animals has ways (Sapolsky, 2005; Squires, 2010). However, been considered as an indicator of the long-term from a welfare viewpoint, interpreting acute and activation of the hypothalamus-pituitary-adrenal mild stress varies among situations and research(HPA) axis. Particularly, there is evidence that hair ers. Acute stress arising from procedures inflicting cortisol (HC) can be used as a measure of the longphysical pain, separation from conspecifics, and term activation of the HPA axis in various mamdeprivation of food or essential environmental facmals. This review discusses the utility and limitators for the species concerned are considered negations of HC analysis for welfare assessment, mainly tive for animal welfare. Nevertheless, mild stress, based on findings from captive chimpanzees living which is often observed when animals face approin a sanctuary in Japan. First, the methodological priate and solvable challenges in their own environand physiological perspectives of how to to obtain ment, is considered important in improving animal reliable results from HC analysis will be discussed; welfare (Meehan & Mench, 2007; Clark, 2017). and second, the potential of using HC analysis for There is greater consensus on how to interpret longwelfare assessment will be reviewed. A series of term chronic stress, something that is commonly studies on captive chimpanzees show that HC is considered negative for animal welfare (Broom & useful for monitoring the effects of social manageJohnson, 1993). Not only is it challenging for animent on the long-term stress levels in captive chimmals to experience distress over a long period, but panzees. Although further studies are needed to also the long-term activation of the HPA axis can clarify the extent to which HC monitoring can help result in health deterioration such as neuronal cell us understand and improve animal welfare, applicadeath, insulin resistance, muscle and bone atrophy, tion of HC analysis might be useful in investigating poor wound healing, hypertension, and even colsimilar issues in marine mammals. lapse of the immune system to the point of death (Reeder & Kramer, 2005). Therefore, understand