title: The role of acoustic signaling for spacing and group coordination in a nocturnal, pair-living primate, the western woolly lemur (Avahi occidentalis).
abstract: OBJECTIVE
  How social groups govern their distribution in time and space is a central question in socioecology. The aim of this study is to explore the role of acoustic signaling for spacing and cohesiveness in a nocturnal, cohesive, pair-living strepsirrhine.
  
  
  METHODS
  The study was conducted in northwestern Madagascar. Six pairs of Avahi occidentalis were radio-collared and home range usage, vocalizations and call-associated behavior recorded using GPS-based focal animal sampling. Home range size was analyzed using ArcView GIS 3.3. Calls were characterized by a multiparametric sound analysis.
  
  
  RESULTS
  Three frequently used, acoustically distinct call types were identified: the avahee call, the whistle call, and the growling call, the latter is a soft; the two others are loud calls. Call types are given by both sexes and convey individually-specific signatures. Call types are used primarily in the locomotion context in the non-core-area of home ranges. The least common avahee call is responded by the avahee call from farther away. The more common whistle call, given when partners become visually isolated, and the growling call emitted at close distances, were answered by the whistle and the growling call. Results suggest a spacing function for the avahee call and group coordination functions for the other call types.
  
  
  CONCLUSIONS
  Our study provides first empirical evidence for a nocturnal, cohesive pair-living strepsirrhine that vocal signaling represents an important mechanism for spacing, group coordination and decision making. Findings contribute to a better understanding of the evolutionary roots of primate vocal communication.
authors.affiliation: Institute of Zoology, University of Veterinary Medicine Hannover Buenteweg 17, Hannover, D-30559, Germany.
authors.forename: Rindrahatsarana
authors.initials: R
authors.lastname: Ramanankirahina
authors.affiliation: Institute of Zoology, University of Veterinary Medicine Hannover Buenteweg 17, Hannover, D-30559, Germany.|Centre for Comparative and Evolutionary Psychology, Department of Psychology, University of Portsmouth, United Kingdom.
authors.forename: Marine
authors.initials: M
authors.lastname: Joly
authors.forename: Marina
authors.initials: M
authors.lastname: Scheumann
authors.affiliation: Institute of Zoology, University of Veterinary Medicine Hannover Buenteweg 17, Hannover, D-30559, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005260:Female; D006702:Homing Behavior / Q000502:physiology; D007900:Lemur / Q000502:physiology*; D008270:Madagascar; D008297:Male; D013018:Sound Spectrography; D013037:Spatial Behavior / Q000502:physiology*; D014828:Vocalization, Animal / Q000502:physiology*
keywords: communication; evolution; phylogenetic hypothesis; sociality complexity hypothesis; woolly lemur