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The diagnosis of psychopathologies in nonhuman primates has received increasing interest in the last decade. However, only a limited number of categories of pathology have been diagnosed in some chimpanzees exclusively by using adapted versions of the Diagnostic and Statistical Manual of Mental Disorders (DSM). With this in mind, we have created a questionnaire for the assessment of psychopathologies in 23 rescued ex-performer and ex-pet chimpanzees, based on an inclusion-exclusion adaptation of the fifth edition of the DSM. A total of 70 items were retained for the Chimpanzee Psychopathology Questionnaire in accordance with 3 main criteria: deleting those that could not be applied to the subjects, retaining those that could be applied, and adapted when needed. Principal component analysis and regularized exploratory factor analysis revealed 9 statistically significant factors with acceptable standards of interrater reliability and validity, accounting for 70.78 % of the variance. The factors obtained were clear and similar to some of the main categories of diagnosis for humans. Nevertheless, the limitation of the sample, the subjectivity in the creation of the questionnaire, as well as the theoretical and methodological challenges of the adaptation of the DSM to chimpanzees, led to the fact that this research should be considered as a first contact study on the identification of disorder categories in a group of chimpanzees. The main purpose of this study is to start a debate to promote research on psychopathology in chimpanzees and other animals. Likewise, it is important to emphasize that the diagnosis of psychiatric disorders in chimpanzees could be translated to important pragmatic aspects for the species related to awareness, legal implications, welfare, and comparative psychopathology.

Chimpanzee’s nocturnal sleep is a dynamic and complex process, still not fully understood. As in humans, not getting enough quality sleep due to frequent or lasting disruptions may affect their physical and mental health, hence wellbeing, which may be reflected in their daytime behavior. This study aims to understand the impact of abiotic factors, such as temperature and humidity on the nocturnal activity as well as the impact of nocturnal awakening events on daytime behavior in sanctuary-housed chimpanzees. We monitored noisy nocturnal activity through audio recordings for one year, documenting the number and duration of sound events produced by chimpanzees to indicate sleep fragmentation and disruption intensity, respectively. Our results indicate that indoor temperature and humidity indeed influence the chimpanzee’s nocturnal activity. Furthermore, sleep fragmentation and intensity of nocturnal events significantly influenced the following day’s behavior. After nights marked by frequent and/or intense sleep disruptions, higher levels of inactivity, and abnormal and self-directed behaviors were observed, and chimpanzees spent more time on affiliative interactions and in social proximity. These findings highlight the importance of controlling factors influencing nocturnal sleep quality. Furthermore, we demonstrated that economic audio recordings used to monitor nocturnal activity, provide insights into the chimpanzee’s behavior and wellbeing.

Advances in the field of social network analysis facilitate the creation of multiplex networks where several interaction types can be analysed simultaneously. In order to test the potential benefits of this approach, we investigated the sociability of atypically raised chimpanzees by constructing and analysing 4-layered multiplex networks of two groups of former pet and entertainment chimpanzees (Pan troglodytes). These networks are based on four social interaction types (stationary vicinity, affiliative behaviour, allogrooming, passive close proximity) representing low- to high-level interaction types in terms of sociability. Using the tools provided by the MuxViz software, we could assess and compare the similarity and information gain of each these social interaction types. We found some social interaction types to be more similar than other ones. However, each social interaction type imparted different information. We also tested for a possible impact of the chimpanzees’ biographical background on the social interaction types and found affiliative behaviour as well as allogrooming to be affected by adverse early life experiences. We conclude that this multiplex approach provides a more realistic framework giving detailed insight into the sociability of these chimpanzees and can function as a tool to support captive care management decisions Te research leading to these results has received funding from ”La Caixa” Foundation (EMCOBA Project, grant number LCF/PR/PR17/11120020) to DC and ML. ML is a Serra Húnter fellow

The long-term effects of early life adversities on social capacities have been documented in humans and wild-caught former laboratory chimpanzees (Pan troglodytes). However, former pet and entertainment chimpanzees have received little attention to date. This study aimed to investigate the long-term effects of early life experience on 18 former pet and entertainment chimpanzees, based on social grooming data collected at a primate rescue centre over a 12-year period. Moreover, we also focused on the possible short-term effects that alterations to group composition might have on grooming patterns. For this purpose, we compared stable and unstable periods (i.e. where alterations to group composition occurred). We used two individual social network measures to analyse the grooming activity and the distribution of grooming among group mates for each individual. We could show that wild-caught chimpanzees were significantly more selective regarding their grooming partners and spent less time grooming when compared to their captive born companions. We also found that individuals who were predominantly housed without conspecifics during infancy spent less time grooming compared to those who were predominantly housed with conspecifics during infancy. Furthermore, we found that alterations to the group composition had short-term effects on the distribution of social grooming from a more equal distribution during periods with a stable group composition towards a more unequal and selective distribution during unstable periods. Thus, we conclude that the social grooming networks of former pet and entertainment chimpanzees are shaped not only by long-term effects such as early life experience, but also by short-term effects such as alterations to group composition. Remarkably, we found not only captive born chimpanzees but also wild-caught individuals to adjust their grooming to socially challenging situations by modifying their grooming distribution in a similar way This research has been funded by: (1) the Spanish Ministerio de Ciencia e Innovación (HAR2009-07223/HIST), (2) Ministerio de Economía y Competividad (HAR2012-32548), (3) Generalitat de Catalunya (2009 SGR-188; 2014 SGR-899; 2017 SGR-1040), (4) Fundação para a Ciência e a Tecnologia (PTDC/PSI-PCO/104170/2008), (5) Universitat Rovirai Virgili (2009AIRE-05;2005ACCES-13), (6) The project leading to these results has received funding from “la Caixa” Foundation (EMCOBA Project), under agreement LCF/PR/PR17/11120020 to ML and DC

The genus Pan is the closest related to humans (Homo sapiens) and it includes two species: Pan troglodytes (chimpanzees) and Pan paniscus (bonobos). Different characteristics, some of biomedical aspect, separate them from us. For instance, some common human medical conditions are rare in chimpanzees (menopause, Alzheimer disease) although it is unclear to which extent longevity plays an active role in these differences. However, both humans and chimpanzees present similar pathologies, thus, understanding traits in chimpanzees can help unravel the molecular basis of human conditions. Here, we sequenced the genome of Nico, a central chimpanzee diagnosed with a particular biomedical condition, the Chiari malformation. We performed a variant calling analysis comparing his genome to 25 whole genomes from healthy individuals (bonobos and chimpanzees), and after predicting the effects of the genetic variants, we looked for genes within the OMIM database. We found a novel, private, predicted as damaging mutation in Nico in LRP5, a gene related to bone density alteration pathologies, and we suggest a link between this mutation and his Chiari malformation as previously shown in humans. Our results reinforce the idea that a comparison between humans and chimpanzees can be established in this genetic frame of common diseases. M.S.-M. is supported by the Ministerio de Economía y Competitividad, Spain (Maria de Maetzu grant MDM-2014-0370-16-3). M.d.M. is supported by a Formació de personal Investigador fellowship from Generalitat de Catalunya (FI_B01111). J.H.-R. is supported by the Ministerio de Economía y Competitividad, Spain (FPI grant BES-2013-064333). C.F. is supported by La Caixa Foundation. A.N. is funded by MINECO BFU2015-68649-P. T.M.-B. is supported by MINECO BFU2014-55090- P (FEDER), U01 MH106874 grant, Howard Hughes International Early Career, La Caixa Foundation and Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya.