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Alpha Male (alpha + male)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Paternity and social rank in wild chimpanzees (Pan troglodytes) from the Budongo Forest, Uganda

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2010
Nicholas E. Newton-Fisher
Abstract We analyzed patterns of paternity and male dominance rank in the Sonso community of wild East African chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda. Our major objective was to determine whether and how social rank influenced paternity success. We successfully genotyped 52 individuals at up to nine microsatellite loci, using DNA extracted from fecal samples. Of 24 offspring analyzed, we identified sires for 21. Paternity success was significantly correlated with social rank, with alpha males siring a disproportionate number of offspring. However, both middle- and low-ranking males also fathered offspring, and the priority-of-access model provided a relatively poor prediction of which males would be successful and under what circumstances. The concentration of paternities among only seven males and the tendency for high-ranking males to sire offspring of multiparous females suggest that both individual variation in male quality and the resource value of particular females may be mediating factors. In comparison with other chimpanzee studies, our results support the hypothesis that larger male cohort size reduces the ability of the alpha male to monopolize females, though within our study, male number did not affect the success of the alpha. Successful sires were not necessarily those who achieved the highest mating success with the females whose offspring they sired, but were those who demonstrated higher investment by spending significantly more time in association with these females. Finally, we estimate extra-group paternity at 0,5%, supporting other evidence that the community serves as the primary reproductive unit in chimpanzees. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source]

Relatedness in wild chimpanzees: Influence of paternity, male philopatry, and demographic factors

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2008
Eiji Inoue
Abstract In chimpanzees (Pan troglodytes), high-ranking males are expected to have high reproductive success and females typically emigrate upon reaching maturity. Although high average relatedness among males in the same social groups has been assumed, previous reports have indicated that relatedness among males is not necessarily significantly higher than that among females. The paternity of 11 offspring and the relatedness of 50 individuals in the M group of chimpanzees at Mahale Mountains National Park, Tanzania, were investigated using DNA analyses. We determined the fathers of 10 offspring. Two different alpha males sired a total of five offspring, whereas the other males had low reproductive success. The proportion of paternal half-sibling pairs among the 10 offspring was 15.6%. The average relatedness among mature males was significantly higher than that among mature females. The existence of an old male and the long tenure of one alpha male may have contributed to this significant difference. The average dyadic relatedness among mature natal individuals was significantly higher than that in natal-immigrant pairs in which the individuals came from different groups. The average relatedness among immigrant females was similar to that in pairs of natal and immigrant females, suggesting that the immigrants came from various groups. Thus, female transfer acts to maintain low average relatedness within the group. A comparison of our results to those from other study sites suggests that although the average relatedness among adult males does not reach the level of half-siblings, under some circumstances it can exceed the relatedness of females. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc. [source]

Why do captive tufted capuchins (Cebus apella) urine wash?

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2008
Kimran E. Miller
Abstract Urine washing (UW) has been observed in numerous species of prosimians and New World monkeys. The functional significance of UW in Cebidae, specifically, Cebus apella, has not been determined. The objective of our study was to test two major hypotheses related to the function of UW: (1) UW functions as a thermoregulatory mechanism, and (2) UW functions as a means of social communication related to (a) territoriality, (b) sexual encounters, or (c) intragroup aggression/agitation. We collected focal data on a captive group of 28 tufted capuchins (C. apella; July,October 2004 and February,July 2005). We found no significant correlation between UW rates and temperature, at a constant, moderate humidity level. Rates of UW were significantly greater outdoors (no conspecific neighbors) vs. indoors (conspecific neighbors). Qualitative evidence suggests a relationship between UW by the alpha male and sexual solicitations from females. UW rates associated with aggression received were significantly higher than UW rates associated with aggression given and UW rates associated with potential fear/stress. There was also a significant negative correlation between cortisol measures and UW frequencies. Our results suggest that UW does not function in thermoregulation or in territorial communication. Alternatively, our results suggest that UW may be associated with sexual encounters and receiving aggression. Additionally, further investigation is warranted to determine whether UW is used as an appeasement mechanism or as a stress reliever or as both. Am. J. Primatol. 70:119,126, 2008. © 2007 Wiley-Liss, Inc. [source]

Scent-Marking of Giant Otter in the Southern Pantanal, Brazil

ETHOLOGY, Issue 3 2009
Caroline Leuchtenberger
Giant otters live in social groups, consisting of a mating pair and one or two litters. Groups are territorial and mark their territories often with scent-marks. Our objectives were to evaluate the frequencies of marking and over-marking according to the social status of the individuals and to define the different postures used during the marking. We observed four groups, totaling 25 individuals (five alpha males, four alpha females, seven adult females, one adult male and eight juveniles) with group size ranging between four and 13 individuals. The study was conducted between July 2006 and July 2007 in the Vermelho River and in a stretch of the Miranda River, in the Southern Pantanal. We observed the groups for a total of 2006 min and recorded 95 events of marking totaling 84.9 min. Time spent marking varied between groups and ranged from 4.3 to 44.7 min. The alpha males marked more frequently (62% of marking events, 55 min) than the alpha females (17% of marking events, 13.6 min). Of the 59 events of scent-marking by the alpha males, 32 over-marked the marks of other individuals from the group. Of the 16 events of scent-marking of the alpha females, five over-marked that of other females from the same group. When scent-marking, alpha males used the ,stepping' posture most frequently (63%), then ,fore-paw rubbing' (24%), ,latrine use' (7%), and ,body rubbing' (6%). Alpha females used the ,stepping' posture most frequently (65%), then ,latrine use' (19%) and ,fore-paw rubbing' (12%), with only one event of ,body rubbing' observed during marking. Subordinate females used the ,stepping' posture (76%) and ,latrine use' (24%) during marking. Scent-marking can play many roles in mammals and for giant otters, and the main roles appear to be communication of social and sexual status and territorial defense. [source]

Paternity and social rank in wild chimpanzees (Pan troglodytes) from the Budongo Forest, Uganda

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2010
Nicholas E. Newton-Fisher
Abstract We analyzed patterns of paternity and male dominance rank in the Sonso community of wild East African chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda. Our major objective was to determine whether and how social rank influenced paternity success. We successfully genotyped 52 individuals at up to nine microsatellite loci, using DNA extracted from fecal samples. Of 24 offspring analyzed, we identified sires for 21. Paternity success was significantly correlated with social rank, with alpha males siring a disproportionate number of offspring. However, both middle- and low-ranking males also fathered offspring, and the priority-of-access model provided a relatively poor prediction of which males would be successful and under what circumstances. The concentration of paternities among only seven males and the tendency for high-ranking males to sire offspring of multiparous females suggest that both individual variation in male quality and the resource value of particular females may be mediating factors. In comparison with other chimpanzee studies, our results support the hypothesis that larger male cohort size reduces the ability of the alpha male to monopolize females, though within our study, male number did not affect the success of the alpha. Successful sires were not necessarily those who achieved the highest mating success with the females whose offspring they sired, but were those who demonstrated higher investment by spending significantly more time in association with these females. Finally, we estimate extra-group paternity at 0,5%, supporting other evidence that the community serves as the primary reproductive unit in chimpanzees. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source]

Relatedness in wild chimpanzees: Influence of paternity, male philopatry, and demographic factors

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2008
Eiji Inoue
Abstract In chimpanzees (Pan troglodytes), high-ranking males are expected to have high reproductive success and females typically emigrate upon reaching maturity. Although high average relatedness among males in the same social groups has been assumed, previous reports have indicated that relatedness among males is not necessarily significantly higher than that among females. The paternity of 11 offspring and the relatedness of 50 individuals in the M group of chimpanzees at Mahale Mountains National Park, Tanzania, were investigated using DNA analyses. We determined the fathers of 10 offspring. Two different alpha males sired a total of five offspring, whereas the other males had low reproductive success. The proportion of paternal half-sibling pairs among the 10 offspring was 15.6%. The average relatedness among mature males was significantly higher than that among mature females. The existence of an old male and the long tenure of one alpha male may have contributed to this significant difference. The average dyadic relatedness among mature natal individuals was significantly higher than that in natal-immigrant pairs in which the individuals came from different groups. The average relatedness among immigrant females was similar to that in pairs of natal and immigrant females, suggesting that the immigrants came from various groups. Thus, female transfer acts to maintain low average relatedness within the group. A comparison of our results to those from other study sites suggests that although the average relatedness among adult males does not reach the level of half-siblings, under some circumstances it can exceed the relatedness of females. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc. [source]