Emerging relationships in a new group of Western lowland gorillas Gorilla gorilla gorilla at Riverbanks Zoo & Garden, Columbia, SC

Abstract

Behavioural interactions among members of a newly formed group of Western lowland gorillas Gorilla gorilla gorilla are analysed, from the early stages of group formation through the first several months after introduction. The group consisted of a male, two half‐sisters and an unrelated female. Data were collected in 15 minute focal animal samples for 3 hours twice a week in two 9 week observation blocks for a total of 99·25 observation hours. Hypotheses tested included: frequency of affiliative behaviours would increase over time, with more affiliative interactions between related females; and agonism would decrease over time. Overall, the mean rates of either behaviour type did not change between observation blocks (affiliative: P = 0·075; agonistic: P = 0·116) Total dyadic rates of affiliation were different in female–male dyads (P < 0·001) but not in female–female dyads (P = 0·525). Dyadic mean rates of agonism from both observation blocks were not different in either female–male or female–female dyads (P = 0·210). Using data from approach–withdrawal and grooming interactions, no strong dominance hierarchy was found among females, despite the relatedness of two of the three females. In general, the focal group exhibited group‐wide and intrasex relationships similar to those documented in other gorilla groups in zoos and in the wild, particularly with regard to the lack of consistent female social dominance.

How is Western Lowland Gorilla (Gorilla gorilla gorilla) Behavior and Physiology Impacted by 360 Degree Visitor Viewing Access?

“…A few studies on solitary grooming have demonstrated that increased self-scratching and auto grooming rates can be linked with stressful situations and increase physiological stress (Castles et al, 1999;Clark et al, 2012;Leeds & Lukas, 2018;Maestripieri et al, 1992;Schino et al, 2007). However, extensive research examining grooming behavior broadly in primates and gorillas notes a significant relationship between grooming and social hierarchy (Huskisson & Chism, 2018;Robbins et al, 2005;Watts, 1994). It is difficult to discern whether the behavior results seen here are stress-related or socially influenced given the limited research comparing gorilla solitary grooming to other behaviors, physiology, and the presence of visitors.…”

Studying primate personality in zoos: implications for the management, welfare and conservation of great apes

“…This could lead to a reduction of aggressive encounters, because gorillas rated lower for Understanding were also more likely to engage in noncontact aggression (Kuhar et al, 2006). It has been suggested that gorilla groups should be formed when the apes are young for the best outcomes (Stoinski et al, 2004), so it is vital to understand any agerelated differences in personality, but this is not always possible in zoos (see Huskisson & Chism, 2018 (King, J. E., et al, 2008). In orangutans, Agreeableness declines with age, and while Extraversion also decreases as orangutans age, it does so differently from Chimpanzees (Weiss & King, 2015).…”