Himalayan langurs: Temperate colobines

Abstract

Four field studies of the langur monkey, Presbytis entellus, living in the Himalaya are compared, in order to uncover shared features of behavior and population structure that may be related to this habitat. Shared demographic characteristics include seasonality in mating and births, predominately multi-male troops at least during some times of the year, relatively large home ranges, low population densities with few intertroop encounters, and seasonal utilization of home ranges with distance maintenance between groups. Shared social characteristics include behavioral buffers against cold and inclement weather, fluctuation in male membership with greatest instability and lowest numbers during the mating season, a vocal repertoire marked by a unique vocalization of major importance in troop maintenance as well as alterations in the function of species-typical vocalizations, and variations in sexual behavior including variable expression of “typical” female headshake present, increased male initiation of sexual activity and a low incidence of female harrassment of sexual consorts. It is argued that while no single feature may be unique to Himalayan langur populations, the total cluster of features is, and can be related to climatic seasonality in the Himalayan temperate environment, the predominance of a multi-male group structure for some periods, and possibly genetic isolation.