Development of bed-building behaviors in captive chimpanzees (Pan troglodytes): Implication for critical period hypothesis and captive management

Wild great apes build beds for sleeping by combining tree branches or other vegetation, but the development of this behavior is poorly understood. We investigated the development of bed-building behaviors by conducting complementary cross-sectional and longitudinal studies of captive chimpanzees. In the cross-sectional study, we created an ethogram of behaviors related to bed-building by observing 59 chimpanzees living at the Kumamoto Sanctuary, Kyoto University, and the Kyoto City Zoo. In the longitudinal study, we installed bed-building platforms, provided branches on the platforms on a regular basis, and recorded behaviors of five chimpanzees (including an infant born in 2013) over a 3-year period from February 2015 to February 2018 at the Kyoto City Zoo (total 490.7 h). We found that all the chimpanzees performed some form of bed-building behavior but wild-born chimpanzees possessed more sophisticated techniques than captive-born chimpanzees. We also found that although the offspring of a wild-born female only showed simple techniques at the beginning of the longitudinal study, his repertoire of bed-building behaviors became as complex as that of his mother by the age of five. Our results suggest that improved bed-building behaviors can be supported in captive-born great apes by providing learning opportunities during appropriate stages of development

Perspective Chapter: Prevention of COVID-19 at Our University

With the rapid spread of the new coronavirus, COVID-19, many universities switched to online classes to promote social distancing and reduce the risk of infection. The Ministry of Education, Culture, Sports, Science and Technology, however, requested universities hold face-to-face classes whenever possible. Therefore, after the national emergency was lifted, our university, the Kinjo University in Hakusan, launched the “Kinjo Infection Control Team” to help prevent infection on campus. Our university was one of the first universities in the Hokuriku region to resume face-to-face classes. Infection control teams were originally organized at hospitals and other medical facilities by professionals specializing in infection prevention and control. Although our university did not have an affiliated hospital, we had medical professionals, including doctors and nurses, as well as virology researchers, who conducted environmental patrols, hand hygiene education and monitoring, and infection education for students and faculty. The most important countermeasures against the spread of infectious disease in universities are the maintenance of the campus environment and the behavioral changes of students. To maintain a safe learning environment during a pandemic, it is necessary to consider the best measures to prevent infection from various aspects so that we can avoid spreading infectious diseases, and also maintain maximum student activity and provide a safe learning environment at all times

Social relationship and hair cortisol level in captive male chimpanzees (Pan troglodytes)

Understanding how social relationships affect long-term stress is important because stress has a profound impact on the welfare of animals and social relationships often exert a strong influence on their stress responses. The purpose of this study was to investigate the relationship between social behaviors and long-term stress levels as assessed by hair cortisol (HC) concentration. The subjects were 11 chimpanzees living in an all-male group (divided into two sub-groups) in Kumamoto Sanctuary, Kyoto University, Japan. Behavioral data were collected between December 2014 and March 2015. The total observation time was 129 h. Hair samples were collected in late March and early April 2015, and cortisol was extracted from the hair and measured with enzyme immunoassay. The hair growth rate was estimated to be 1.33 ± 0.06 cm/month. The results revealed that there was a positive correlation between the rate of receiving aggression and HC levels. We also found a significant negative correlation between the balance between giving and receiving grooming (grooming balance index: GBI), which was calculated by subtracting the rate with which grooming is given from that with which it is received, and the rate of receiving aggression and between the GBI and HC levels. Thus, individuals receiving higher levels of aggression also tended to give grooming for relatively long periods compared to the time they were being groomed. In contrast, the rate of initiating aggression did not have a relationship with either HC levels or any measure of social grooming. We did not find social buffering effects, as there was no correlation between mutual social grooming and HC levels. These results show that not only aggressive interactions but also overall social situations in which animals do not have balanced relationships with others might result in the long-term elevation of cortisol levels in captive male chimpanzees

Chimpanzee Down syndrome: a case study of trisomy 22 in a captive chimpanzee

We report a case of chimpanzee trisomy 22 in a captive-born female. Because chromosome 22 in great apes is homologous to human chromosome 21, the present case is analogous to human trisomy 21, also called Down syndrome. The chimpanzee in the present case experienced retarded growth; infantile cataract and vision problems, including nystagmus, strabismus, and keratoconus; congenital atrial septal defect; and hypodontia. All of these symptoms are common in human Down syndrome. This case was the second reported case of trisomy 22 in the chimpanzee. The chimpanzee in our case became blind by 7 years old, making social life with other chimpanzees difficult, but opportunities to interact with other conspecific individuals have been offered routinely. We believe that providing her with the best care over the course of her life will be essential