Is Chimpanzee (Pan troglodytes) Wounding Frequency Affected by the Presence Versus Absence of Visitors? A Multi-Institutional Study

Visitor effect studies have had inconsistent results, due in part to the inability control for all confounding variables such as time of day, seasonal weather patterns, and so forth. This study represents first instance where chimpanzee (Pan troglodytes) wounding frequencies were investigated across extensive periods presence complete absence visitors, thus eliminating many visitor-related variables. Additional eliminated through zoo selection process, based on institutional responses a 29-question survey, providing novel approach question visitor effects. The aim this was determine if visitors associated with change wound event four 51-day conditions, three which occurred prior COVID-19 pandemic, one during wave pandemic-related closures. We analyzed archival records 21 chimpanzees housed at U.S. zoos. Due small number events windows, “no wound” analyzed. A chi-square goodness fit test performed whether frequency equal between “open” “closed” trials. Results indicate that did not differ, suggesting welfare, it relates wounding, may be adversely affected by visitors.