Abstract:The Semnopithecus entellus can be broadly classified into two morphotypes based on tail carriage, namely the northern and the southern types (NT & ST). The borderline between these morphotypes runs along the Tapti-Godavari rivers in peninsular India. However there have been anecdotal reports of range extension of NT in peninsular India. To investigate this scenario we undertook an intensive survey of S. entellus morphotypes along the borderline districts in the states of Gujarat, Maharashtra, Karnataka and Andhra Pradesh. The GPS coordinates of the two morphotypes were mapped using MapInfo professional software and the resulting map was compared with the map generated by Roonwal. Results indicate that NT S. entellus range limit fall further south of Roonwal's borderline. This incongruence in NTs distribution between the present study and Roonwal's might be due to natural range extension of NTs in some areas or a product of sampling artifact. Furthermore in parts of Andhra Pradesh and Karnataka human mediated translocations might have also contributed to this range extension.Keywords: Anthropogenic activity, hybrid zone, peninsular India, range limit, river, tail carriage, under sampling. Acknowledgements:The study was financially supported by the Department of Biotechnology, Government of India (BT/PR-7127/ BCE/08/445/2006) and Ministry of Environment and Forest. We are grateful to the forest departments of Maharashtra, Karnataka, and Andhra Pradesh forest for permissions and cooperation. Special thanks to Chaitra, Achyuthan, Anjana Shenoy, Rishikesh Bahadur Desai, Rishi Kumar, Santosh Shanbhag, Sridhar Gadiyar, Kushal Kamble, Harish Bhat, Laurens Verwijs, Martin Zaruba, Hanka Svobodova, affiliates of Karanth laboratory for their generous support during the study. We like to thank K.V. Gururaja who helped us with drawing the maps. We also like to thank the reviewers for their constructive comments on the manuscript.