Pheromone aggregation, snakes

Graves B.M., Halpem M. and Friesen J.L. (1991). Snake aggregation pheromones source and chemosensory mediation in Western Ribbon snakes (Thamnophis proximus). J Comp Psychol 105, 140-144. 

Aggregations of female snakes that are nearing parturition have been recorded for several species (Duvall et al., 1985 Gregory, 1975 Henderson et al., 1980 Shine, 1979), Females may be aggregating at this time because of a scarcity of suitable refugia or to swamp predators with a mass crop of young. Whether pheromone trails are involved in the formation of these aggregations has not been examined. 

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