title: Who is coordinating collective movements in black and gold howler monkeys?
abstract: Decisions about when and where to travel are likely to have a strong influence on the feeding, ecology, and foraging strategies of individual primates living in a cohesive social group. Specifically, given differences in age, sex, reproductive status, or social dominance, particular group members may benefit from remaining at their present location while others may benefit from traveling to another area of their range to feed or rest. In this study, we present data on movement coordination in two groups of wild black and gold howler monkeys inhabiting Isla Brasilera (27º 20'S and 58º 40'W) in northern Argentina. We examine how factors such as sex, age, reproductive status, and dominance affect patterns of group movement coordination at feeding or resting sites, and in the context of intergroup encounters. Two groups were followed five days a month from sunrise to sunset during June to November 2004. Using focal and scan sampling techniques, we recorded 262 group displacements, the identity of the individual initiating and leading displacement, and the identity of the first individual to arrive at feeding, resting, or intergroup encounter sites. We found that overall age was the only factor that influenced group coordination: adults led more often (94.5 %) than immature individuals (5.5 %) in both groups. We did not find differences among adults. However, we found that males lead more often than females at intergroup encounters, consistent with the male-mate defense hypothesis. The distributed leadership pattern among adults observed in this study may suggest that adult individuals make equally shared consensus decisions. This pattern should be further examined using this individual-level approach in other populations of black and gold howlers, other species of howlers, and in other atelines in which within-group social tolerance is the rule rather than the exception.
authors: Estación Biológica Corrientes-Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470, C1405DJR, Buenos Aires, Argentina. vanifer@gmail.com
authors: Vanina A
authors: VA
authors: Fernández
authors: Martín
authors: M
authors: Kowalewski
authors: Gabriel E
authors: GE
authors: Zunino
mesh_terms: D000375:Aging; D000508:Alouatta / Q000502:physiology*; D000818:Animals; D001118:Argentina; D005260:Female; D006702:Homing Behavior; D008297:Male; D012727:Sex Characteristics; D012930:Social Dominance
references: Int J Primatol. 2011 Dec;32(6):1268-1278
references: 22207769
references: Nature. 2003 Jan 9;421(6919):155-8
references: 12520299
references: Am J Phys Anthropol. 1999 Mar;108(3):295-310
references: 10096681
references: Behav Processes. 2010 Jul;84(3):678-80
references: 20350590
references: Am J Primatol. 2008 Mar;70(3):282-93
references: 17894404
references: Anim Cogn. 2007 Jul;10(3):305-15
references: 17297617
references: Behav Processes. 2010 Jul;84(3):681-4
references: 20211229
references: Folia Primatol (Basel). 1981;36(1-2):40-75
references: 7338334
references: Am J Primatol. 2009 Feb;71(2):153-64
references: 19016487
references: Behaviour. 1974;49(3):227-67
references: 4597405
references: Behav Processes. 2010 Jul;84(3):635-47
references: 20435103
references: Am J Phys Anthropol. 2011 May;145(1):137-46
references: 21365610
references: Am J Primatol. 2003 Dec;61(4):145-57
references: 14669267
references: Am J Primatol. 2010 Aug;72(8):734-48
references: 20568080
references: Behav Processes. 2008 May;78(1):84-92
references: 18281161
references: Trends Ecol Evol. 2005 Aug;20(8):449-56
references: 16701416
references: Int J Primatol. 2011 Dec;32(6):1325-1347
references: 22207771