Proximity patterns of female western lowland gorillas (Gorilla gorilla gorilla) during the six months after parturition

Abstract

Studies of wild mountain gorillas have demonstrated strong preferences among new mothers for the silverback. Protection against infanticide has been theorized to be the primary cause for this attraction. We examined social partner preferences in captive western lowland mothers during the 6 mo after parturition and found that juveniles and females were the primary members of the new mothers' social network. Mothers spent significantly more time in close proximity with both of these subgroups than with the silverback. Proximity patterns changed over time: new mothers spent more time near females in the month after parturition than in the month prior to parturition, and spatial proximity increased again in months 2-6 postparturition. These findings differ from those reported for wild mountain gorillas, which may reflect the lack of infanticide risk in captivity. Given current hypotheses that infanticide may be a limited in western lowland gorillas, the social partner preferences observed here may be indicative of patterns in wild populations.

Reconciliation and Consolation in Captive Western Gorillas

“…Because the primary social structure in both species seems to be similar with the presence of 1 dominant silverback, several mature females and their immature offspring (Parnell, 2002;Stokes et al, 2003;Watts, 1995a;2003), it would be interesting to verify if post-conflict strategies are comparable as well. Even if studies on the social system of western gorillas have for most part relied on indirect observations, e.g., night-nest counts (Parnell, 2002;Stokes et al, 2003), researchers report an organization similar to that of mountain gorillas, yet with some exceptions: e.g., allmale or multimale groups are very rare in populations of western gorillas (Parnell, 2002;Stoinski et al, 2003;Stokes et al, 2003). All known gorilla populations seem to be characterized by female and male dispersal and a polygynous mating system (Parnell, 2002;Stokes et al, 2003;Watts, 1995a;Yamagiwa et al, 2003).…”

Postconflict behavior in captive western lowland gorillas (Gorilla gorilla gorilla)

“…First, female dominance hierarchies appear to be more clearly established in western lowland gorillas than in mountain gorillas [Scott & Lockard, 1999]. Second, in contrast to mountain gorilla groups, western lowland gorilla females have been observed to spend significantly more time with other females than with silverbacks [Stoinski et al, 2003a], and to coexist without a male [Stoinski et al, 2003b]. These differences in sociality suggest a higher level of female bonding in western lowland gorillas, which could promote the need for reconciliation to maintain close social bonds.…”

Human–animal relationships in zoo‐housed orangutans (P. abelii) and gorillas (G. g. gorilla): The effects of familiarity

“…Behaviors were classified, based on behavioral similarity or apparent behavioral ends, into four types: visual, aggressive, hiding, and affiliative (see Table II for full descriptions of HDBs). Additionally, affiliative behaviors, were designated as close (<3 m) or distant (>3 m), consistent with proximity definitions for studies of zoo orangutans and gorillas [Edwards & Snowdon, 1980;Less et al, 2010;Nakamichi & Kato, 2001;Poole, 1987;Stoinski et al, 2003Stoinski et al, , 2004Whilde & Marples, 2011;Zucker & Thibaut, 1995].…”