The genus Semnopithecus in south India is represented by the Nilgiri langur (S. johnii) and the common Hanuman langur (S. priam thersites). The Nilgiri langur is an endemic to the Western Ghats and is a threatened species while the status of the common langur, an endemic to the Indian‐subcontinent, is not known due to deficient data. The lack of knowledge of their distribution, ecology and status makes it difficult for informed conservation initiatives. These closely related langur species have been reported to hybridize in regions where their ranges adjoin i.e. regions where they are parapatric. The mechanism by which such parapatry is maintained is of considerable importance in understanding the evolution and speciation of the genus. A comparative study of their distribution and ecology is imperative for elucidating these mechanisms.
- How are the two langur species distributed with respect to each other and to what extent are they distributed parapatrically within the southern Western Ghats region?
- What role do environmental gradients (gradients in altitude and vegetation) play in maintaining the pattern of distribution of each species?
- At a given site where the range of the two species overlaps, what role do ecological factors including inter‐specific competition and intestinal parasite loads play in maintaining the pattern of distribution of each species?
Sunita Ram