Abstract # 206:

Scheduled for Sunday, September 18, 2011 07:00 PM-09:00 PM: Session 23 (Salon F (Sixth Floor)) Poster Presentation


CONTEXT AND BEHAVIOR DEPENDENT HIERARCHY IN WILD LEMUR CATTA AND PROPITHECUS VERREAUXI (BERENTY, SOUTH MADAGASCAR)

I. Norscia, D. Antonacci and E. Palagi
Museo di Storia Naturale e del territorio, Via Roma, 79, Calci, Pisa 56011, Italy
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The presence of a context- and/or behavior-dependent hierarchies, described in primates, has never been quantitatively demonstrated in lemurs. At Berenty (Madagascar), in November 2006-February 2007 and March-July 2008, we gathered data on ringtailed lemurs (two groups of 10 and 13 individuals; 389 observation hs) and Verreaux’s sifaka (two groups of 10 and 6 individuals; 640 observation hs). We collected supplants and aggressions via focal and all occurrences sampling. We assessed hierarchy linearity via binary dyadic relationships (BDR; software: Matman 1.0), using aggression and avoidance sociomatrices. All groups showed linearity (or a trend) (0.60<h’<0,99; 0.00<p<0.07). Only L. catta maintained linearity with avoidance (0.585<h’<0.751; 0.001<p<0.004) but group hierarchy was different. Ringtailed lemur hierarchy stayed linear in both feeding (group A; Nconflicts: 112, h’=0.79, p<0.001; group B; Nconflicts =59, h’=0.46, p=0.03) and non feeding context (group A; Nconflicts: 101, h’=0.91, p<0.001; group B; Nconflicts =76, h’=0.46, p=0.045) whereas sifaka hierarchy was linear in the non feeding context only (group A - Nconflicts: 44, h’=0.56, p<0.04; group B - Nconflicts =42, h’=0.43, p=0.05). Normalized David’s scores (NDS; software: Steepness 1.0) revealed that, even in non-linear hierarchies, females were dominant. These results suggest that more than one hierarchy can coexist at the same time in a lemur group and that the power asymmetry perceived by individuals does not necessarily go in tandem with the asymmetry appearing from agonistic interactions.