Male-female interactions in multimale groups of mountain gorillas

2018 ◽  
Vol 80 (11) ◽  
pp. e22910
Author(s):  
Sosthene Habumuremyi ◽  
Tobias Deschner ◽  
Katie A. Fawcett ◽  
Martha M. Robbins
Keyword(s):  
Mountain Gorillas ◽  
Multimale Groups

A Demographic Analysis of Male Life History and Social Structure of Mountain Gorillas

Behaviour ◽  
1995 ◽  
Vol 132 (1-2) ◽  
pp. 21-47 ◽  
Author(s):  
Martha M. Robbins
Keyword(s):  
Reproductive Success ◽  
Social Structure ◽  
Life Histories ◽  
Demographic Data ◽  
Male Reproductive Success ◽  
Adult Males ◽  
Mountain Gorillas ◽  
Group Type ◽  
Multimale Groups ◽  
Adult Lives

AbstractTwenty-five years of demographic data on free-ranging mountain gorillas (Gorilla gorilla beringei) from the Karisoke Research Center, Rwanda were used to assess male life histories and the variation within the age-graded social structure. Group types include lone silver-backs, one-male, multimale, and all-male groups. Although 60% of gorilla groups in the Virunga population are one-male, a multimale structure may increase chances of survival and future reproductive success for males at three stages of their lives. Infants born in one-male groups appear more likely to die from infanticide than those in multimale groups. Immature males in one-male groups may face decreased future reproductive opportunities compared to males in multimale groups. Adult males in one-male groups lack possible partners for coalition formation during intergroup encounters. Demographic constraints, such as length of time to male maturation, coupled with intense male-male competition for mates may limit the number and duration of groups with a multimale structure. Individuals are not restricted to one group type for their entire adult lives and males that attain maturity in each group type may eventually reproduce. Variation in male reproductive success is based both on length of reproductive tenure and on the number of mates.

scholarly journals Mothers may shape the variations in social organization among gorillas

2016 ◽  
Vol 3 (10) ◽  
pp. 160533 ◽  
Author(s):  
Andrew M. Robbins ◽  
Maryke Gray ◽  
Thomas Breuer ◽  
Marie Manguette ◽  
Emma J. Stokes ◽  
...  
Keyword(s):  
Social Organization ◽  
Phylogenetic Analyses ◽  
Demographic Data ◽  
Adult Males ◽  
Closely Related Species ◽  
Mountain Gorillas ◽  
Limited Support ◽  
Putative Father ◽  
Multimale Groups ◽  
Study Sites

When mothers continue to support their offspring beyond infancy, they can influence the fitness of those offspring, the strength of social relationships within their groups, and the life-history traits of their species. Using up to 30 years of demographic data from 58 groups of gorillas in two study sites, this study extends such findings by showing that mothers may also contribute to differences in social organization between closely related species. Female mountain gorillas remained with their sons for significantly longer than western gorillas, which may explain why male philopatry and multimale groups are more common among mountain gorillas. The presence of the putative father and other familiar males did not vary significantly between species, and we found only limited support for the socio-ecological theory that the distribution of adult males is influenced by the distribution of females. Within each gorilla species, variations in those distributions may also reflect the different stages in the typical life cycle of a group. Collectively, our results highlight the potentially far-reaching consequences of maternal support that extends beyond infancy, and they illustrate the opportunity to incorporate additional factors into phylogenetic analyses of variations in social organization, including studies of human evolution.

Socioecological correlates of energy balance using urinary C-peptide measurements in wild female mountain gorillas

2014 ◽  
Vol 127 ◽  
pp. 13-19 ◽  
Author(s):  
Cyril C. Grueter ◽  
Tobias Deschner ◽  
Verena Behringer ◽  
Katie Fawcett ◽  
Martha M. Robbins
Keyword(s):  
Energy Balance ◽  
Wild Female ◽  
C Peptide ◽  
Mountain Gorillas

scholarly journals Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Edward Wright ◽  
Sven Grawunder ◽  
Eric Ndayishimiye ◽  
Jordi Galbany ◽  
Shannon C. McFarlin ◽  
...  
Keyword(s):  
Body Size ◽  
Competitive Ability ◽  
Dominance Rank ◽  
Male Body ◽  
Honest Signal ◽  
Sexual Competition ◽  
Mountain Gorillas ◽  
Temporal Characteristics ◽  
Gorilla Beringei Beringei ◽  
Vocal Signals

AbstractAcoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication.

Virunga Gorillas – the Case Against Translocations

Oryx ◽  
1977 ◽  
Vol 13 (5) ◽  
pp. 469-472 ◽  
Author(s):  
A. H. Harcourt
Keyword(s):  
National Park ◽  
Careful Consideration ◽  
Mountain Gorillas

Only about 300 mountain gorillas survive in the Virunga Volcanoes of Zaire and Rwanda. In the last Oryx Dr John MacKinnon suggested that a transfer of animals from the Kahuzi-Biega National Park to introduce new blood to the Virunga population should be considered. The author of this article, who spent two years intheVirungaswith Dian Fossey studying the gorillas, points out first that we do not yet know whether the animals are, in fact, suffering from inbreeding, and suggests why they may not be so; and second that there are special difficulties about the transfer that make death of the released animals and disruption of the population the most likely results at present. Dr MacKinnon, who has read the article, agrees that there are many dangers in translocation and that it should not be done without careful consideration and expert supervision.

Proximate composition of milk from free-ranging mountain gorillas (Gorilla beringei beringei)

Zoo Biology ◽  
2010 ◽  
Vol 30 (3) ◽  
pp. 308-317 ◽  
Author(s):  
Christopher A. Whittier ◽  
Lauren A. Milligan ◽  
Felicia B. Nutter ◽  
Michael R. Cranfield ◽  
Michael L. Power
Keyword(s):  
Proximate Composition ◽  
Mountain Gorillas ◽  
Gorilla Beringei Beringei ◽  
Gorilla Beringei ◽  
Free Ranging

scholarly journals Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda

2018 ◽  
Vol 167 (4) ◽  
pp. 930-935 ◽  
Author(s):  
Jordi Galbany ◽  
Thadée Muhire ◽  
Veronica Vecellio ◽  
Antoine Mudakikwa ◽  
Aisha Nyiramana ◽  
...  
Keyword(s):  
National Park ◽  
Age Determination ◽  
Tooth Wear ◽  
Incisor Tooth ◽  
Mountain Gorillas

FEMALE DOMINANCE RELATIONSHIPS AMONG CAPTIVE WESTERN LOWLAND GORILLAS: COMPARISONS WITH THE WILD

Behaviour ◽  
1999 ◽  
Vol 136 (10-11) ◽  
pp. 1283-1310 ◽  
Author(s):  
Joan Lockard ◽  
Jennifer Scott
Keyword(s):  
Natural Habitat ◽  
High Energy ◽  
Gorilla Gorilla ◽  
Female Dominance ◽  
Primate Species ◽  
Dominance Hierarchies ◽  
Mountain Gorillas ◽  
Dominance Relationships ◽  
Western Lowland Gorillas ◽  
Lowland Gorillas

AbstractFemale dominance relationships were studied among three family groups of western lowland gorillas (Gorilla gorilla gorilla) housed in large enclosures at Howletts Wild Animal Park, in Kent, England. In common with gorillas in their natural habitat, the Howletts gorillas forage throughout the day on low nutrient foods. However, the latter differ, at least from mountain gorillas (Gorilla gorilla beringei), in that they also have relatively frequent access to high nutrient, high energy novel food items which are patchily distributed in time and space, and defendable. It was predicted that, despite these differences, the Howletts females would resemble mountain gorillas in forming adult female dominance hierarchies (determined from supplant interactions) in which older females that have lived in the group the longest are dominant to younger females, more recent to the group. The comparison was made with mountain gorillas as they are the only gorilla subspecies for which such data exist for wild-living populations. As predicted, an age/tenure-based dominance hierarchy was found to be the case for those groups at Howletts where there was considerable variation between the females' ages and length of group tenure. As gorillas and chimpanzees resemble more closely each other in forming age/tenure-based dominance hierarchies than they do other female-transfer primate species, it is proposed that the gorilla-chimpanzee pattern may have common phylogenetic origins. In addition, the order of progression of gorillas into their indoor living quarters appears to be a good indicator of supplant-dominance relationships among adult group members. It was also found that, despite being removed from their natural habitat, dominant males in captivity still lead their groups during group travel in the same manner that do males in the wild: either at the head, or bringing up the rear. Though primate social behaviour may be flexible depending on immediate context and life history variables, this flexibility may well remain within evolutionarily defined parameters, leading to species-typical patterns in general social interactions.

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