Where do the langurs criss-cross? Spatial understanding of group composition and habitat of mixed-species groups of Nilgiri langur (Semnopithecus johnii Fischer, 1829) and tufted gray langur (Semnopithecus priam Blyth, 1844) across the Western Ghats, India

Abstract

An overlap of ranges of Nilgiri langurs (Semnopithecus johnii Fischer, 1829) and tufted gray langurs (Semnopithecus priam Blyth, 1844) in the Western Ghats resulted in the formation of mixed-species groups (MSGs) with a notable presence of brown morphs and significant changes in group composition and population dynamics. Our study investigated the composition of MSGs and examine the vegetation in their ranges across the Western Ghats. We identified three new locations with MSGs in the Nilgiris and southern Western Ghats predominantly found in deciduous forests (∼50 %), at an average altitude of 621.01 m asl. The mean group size of MSGs was 10.9 ± 4.49SD The geographic variation in the abundance of Nilgiri and tufted gray langurs, driven by their ecological adaptability and dispersal patterns, provides important insights into their ecological niches in the Western Ghats.