Our project focuses on Purple-faced langurs  (Semnopithecus vetulus)  and Tufted Gray langurs (Semnopithecus priam thersites). While the tufted gray langur remains relatively ubiquitous, ranging successfully across fragmented and urban landscapes, the purple-faced langur is largely confined to remaining forests. These differences are unsurprisingly reflected in the two species’ respective conservation statuses: the tufted gray langur is classified as Near Threatened, while the Critically Endangered purple-faced langur is consistently categorized as one of the 25 most endangered primate species in the world. The northern purple-faced subspecies, S. vetulus philbricki, is found in the north central dry mixed evergreen forests experiencing high levels of anthropogenic influence that hinder their long-term survival. Despite this, the fine scale vegetation correlates that determine the  distribution and abundance of this endemic species remains poorly understood. Moreover, our previous work indicates the potential for natural hybridization between the two species, which may exacerbate the threats experienced by this species. To inform conservation activities and priorities, a better understanding of the differences in distribution, abundance, and genetic structure as well as potential hybridization levels between the two langur species is urgently needed.