Function and maintenance of sexual segregation in the monomorphic guanaco of South America

Bank, Michael S.
Tom Wessels, MA
Department of Environmental Studies
We investigated guanaco (Lama guanicoe) sexual segregation at Torres del Paine National Park, in southern Chile from March 1995 - April 1996. To measure guanaco population distribution, composition, and habitat selection among social group types we conducted population surveys, two hour make group focal observations, and marked animal observations. Additionally, we obtained information on habitat availability, territorial male and male group interactions, and distributions of predators to test the reproductive-strategy hypothesis pertaining to sexual segregation in ungulates. Males and females were segregated from October to February into Male and Family Group Zones. Availability of habitat types differed significantly among Male and Family Group Zones (P < 0.01). All social groups preferred the meadow vega cover type (P < 0.01) and male and family groups avoided trees and shrubs > 1 meter (P < 0.01). The number of pumas observed in Male Group Zones was nearly significantly higher than in Family Group Zones (P = 0.056). Our data supported the hypothesis that sexual segregation in guanacos occurs as a result of different life history and reproductive strategies between males and females.

Read Full Text