Abstract # 7903 Poster # 13:

Scheduled for Saturday, August 26, 2017 06:00 PM-08:00 PM: (National Ballroom AB) Poster Presentation


FALSE DUSK BUT NOT VISITOR NUMBERS INFLUENCE EVENING RETIREMENT BEHAVIORS IN ZOO-HOUSED CHIMPANZEES (PAN TROGLODYTES)

J. Nichols, A. Kwiatt, S. R. Ross and L. M. Hopper
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, 2001 N Clark St., Chicago, Illinois 60614, USA
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     When wild chimpanzees nest for the evening is related to environmental factors such as temperature and weather. In zoos, chimpanzees experience additional potentially influencing factors, such as the presence of visitors, yet the relative influence of these elements on chimpanzee evening retirement behaviors is unknown. Here, retirement behaviors were defined as nest building, sleeping, or inactivity. We investigated if and how the time of day, weather, and crowd size impacted the evening retirement timing of a mixed-sex chimpanzee group (N=6) housed at Lincoln Park Zoo, Chicago, in an exhibit with abundant natural light and daily exposure to zoo visitors. The chimpanzees’ behaviors were recorded via 10-minute focal sessions using 30-second intersample intervals. We analyzed 86 hours of observational data recorded between 2pm and 5pm each weekday from March 2015 to February 2016. The proportion of time chimpanzees spent performing retirement behaviors was best explained by an hour x weather interaction (p<0.001): the proportion of retirement behaviors increased with time and was higher in the 4pm hour when it was overcast. Adding crowd size did not improve the model (p>0.05), suggesting that false dusk (low levels of light due to cloud cover) but not visitor numbers influenced retirement. Findings contribute to existing theories regarding the importance of exhibit design and its possible negation of crowd effects on behavior.