Status and distribution of Mugger Crocodile Crocodylus palustris in the southern stretch of river Cauvery in Melagiris, India

Main Article Content

Rahul Gour
Nikhil Whitaker
Ajay Kartik


A study was conducted to examine the population estimate and spatial distribution of Mugger Crocodile in the southern stretch of river Cauvery, Hosur Forest Division from February 2019 to May 2019. In total, 53 basking sites and 45 Muggers were encountered by direct sighting in the 24-km river stretch using daytime ground based survey approach. N-mixture models estimated an average Mugger density of 2.05 individuals per kilometre for daytime survey. A night spotlight survey across the seven segments of river stretch was also conducted which yielded direct sightings of 54 Muggers with an average encounter rate of 2.25 individuals per kilometre. Two crocodile nests with hatched egg shells were also observed on the sand banks of the river. We concluded that a potential healthy and breeding population of Mugger inhabits the studied stretch of the river. Multiple corresponding analysis was also performed, which demonstrated that Mugger responds to sandy banks alongside deep water pools for basking in contrast to river segments with shallow depth and dense riparian cover.

Article Details

How to Cite
Gour, R., Whitaker, N. and Kartik, A. 2022. Status and distribution of Mugger Crocodile Crocodylus palustris in the southern stretch of river Cauvery in Melagiris, India. Journal of Threatened Taxa. 14, 3 (Mar. 2022), 20733–20739. DOI:


Abdi, H. & L.J. Williams (2010). Principal Component Analysis. Wiley Interdisciplinary Reviews: Computational Statistics 2: 433–459.

Andrews, H.V. (1999). Status and Distribution of the Mugger Crocodile in Tamil Nadu. ENVIS Bulletin: Wildlife & Protected Areas 2(1): 38–43.

Baskaran, N., K. Senthilkumar & M. Saravanan (2011). A new site record of the Grizzled Giant Squirrel Ratufa macroura (Pennant, 1769) in the Hosur forest division, Eastern Ghats, India and its conservation significance. Journal of Threatened Taxa 3(6): 1837–1841.

Bayliss, P. (1987). Survey methods and monitoring within crocodile management programmes, pp. 157–175. In: Webb, G.J.W., S.C. Manolis & P.J. Whitehead (eds.). Wildlife Management: Crocodiles and Alligators. Surrey Beatty and Sons Pty, Sydney.

Brito, J.C., F. Martínez-Freiría, P. Sierra, N. Sillero & P. Tarroso (2011). Crocodiles in the Sahara Desert: An Update of Distribution, Habitats and Population Status for Conservation Planning in Mauritania. PloS ONE 6(2): e14734.

Cherkiss, M.S., F.J. Mazzotti & K.G. Rice (2006). Effects of shoreline vegetation on visibility of American crocodiles (Crocodylus acutus) during spotlight surveys. Herpetological Review 37(1): 37–40.

Choudhury, B.C. & A. de Silva (2013). Crocodylus palustris. 2013 IUCN Red List of Threatened Species: e.T5667A3046723. Downloaded on 14 July 2021.

Da Silva, A. & J. Lenin (2010). Mugger Crocodile Crocodylus palustris. In: Manolis S.C. & C. Stevenson (eds.). Crocodiles. Status Survey and Conservation Action Plan. 3rd Edition. Crocodile Specialist Group, Darwin, Australia.

Dail, D. & L. Madsen (2011). Models for estimating abundance from repeated counts of an open metapopulation. Biometrics 67: 577–587.

Daniels, R.J.R. & N.M. Ishwar (1994). Rarity and the herpetofauna of the Southern Eastern Ghats, India. Cobra 16: 2–14.

Fiske, I. & R. Chandler (2011). unmarked: An R Package for Fitting Hierarchical Models of Wildlife Occurrence and Abundance. Journal of Statistical Software 43(10): 1–23.

Fujisaki, I., F.J. Mazzotti, R.M. Dorazio, K.G. Rice, M. Cherkiss & B. Jeffery (2011). Estimating trends in alligator populations from nightlight survey data. Wetlands 31: 147–155.

Fukuda, Y., W. Saalfeld, G. Webb, C. Manolis & R. Risk (2012). Standardised method of spotlight surveys for crocodiles in the tidal rivers of the Northern Territory, Australia. Northern Territory Naturalist 24(1): 14­–32.

Greenacre, M. & J. Blasius (eds.) (2006). Multiple Correspondence Analysis and Related Methods. Chapman and Hall/CRC, New York, 354pp.

Griffiths, R.A., J. Foster, J.W. Wilkinson & D. Sewell (2015). Science, statistics and surveys: a herpetological perspective. Journal of Applied Ecology 52: 1413–1417.

Hutton, J.M. & M.E.J. Woolhouse (1989). Mark-recapture to assess factors affecting the proportion of a Nile crocodile population seen during spotlight counts at Ngezi, Zimbabwe, and the use of spotlight counts to monitor crocodile abundance. Journal of Applied Ecology 26(2): 381–395.

Kassambara, A. & F. Mundt (2020). factoextra: Extract and Visualize the Results of Multivariate Data Analyses. R package version 1.0.7.

Kéry, M., R.M. Dorazio, L. Soldaat, A. Van Strien, A. Zuiderwijk, & J.A. Royle (2009). Trend estimation in populations with imperfect detection. Journal of Applied Ecology 46: 1163–1172.

Lentic, M. & G. Connors (2006). Changes in the distribution and abundance of saltwater crocodiles (Crocodylus porosus) in the upstream, freshwater reaches of rivers in the Northern Territory, Australia. Wildlife Research 33(7): 529–538.

Le, S., J. Josse & F. Husson (2008). FactoMineR: An R Package for Multivariate Analysis. Journal of Statistical Software 25(1): 1–18.

Messel, H., G.C. Vorlicek, A.G. Wells & W.J. Green (1981). Surveys of Tidal River Systems in the Northern Territory of Australia and their Crocodile Populations. Monograph: Volume 1. The Blyth-Cadell River Systems Study and the Status of Crocodylus porosus in Tidal Waterways of Northern Australia. Methods for Analysis, and Dynamics of a Population of C. porosus. Pergamon Press, Sydney.

R Core Team (2021). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.

Rao, R.J. & B.C. Choudhury (1993). Sympatric distribution of Gharial Gavialis gangeticus and Mugger Crocodylus palustris in India. Journal of the Bombay Natural History Society 89(3): 312–315.

Royle, J.A. (2004). N-mixture models for estimating population size from spatially replicated counts. Biometrics 60: 108–115.

Shenoy, K., S. Varma & K.V.D. Prasad (2006). Factors determining habitat choice of the smooth-coated otter, Lutra perspicillata in a South Indian river system. Current Science 91(5): 637–643.

Singh, L.A.K. (1999). Significance and achievements of the Indian Crocodile Conservation Project. ENVIS Bulletin: Wildlife & Protected Areas 2(1): 10–16.

Tiwari, U. & R. Kaliamoorthy (2018). Floristic Diversity and Vegetation Analysis of Plants from Various Forest Types in Hosur Forest Division, Tamil Nadu, Southern India. Notulae Scientia Biologicae 10(4): 597–606.

Venugopal, D. & K.V.D. Prasad (2003). Basking Behavior and Survey of Marsh Crocodiles Crocodylus palustris in Ranganthittu Bird Sanctuary, Karnataka, India. Hamadryad 27(2): 241–247.

Vyas, R. (2012). Current status of Marsh Crocodiles Crocodylus palustris (Reptilia: Crocodylidae) in Vishwamitri River, Vadodara City, Gujarat, India. Journal of Threatened Taxa 4(14): 3333–3341.

Webb, G.J.W., A.R.C. Britton, S.C. Manolis, B. Ottley & S. Stirrat (2000). The recovery of Crocodylus porosus in the Northern Territory of Australia: 1971–1998, pp. 195–234. In: Crocodiles. Proceedings of the 15th Working Meeting of the IUCN-SSC Crocodile Specialist Group, IUCN, Gland, Switzerland.

Whitaker, R. (1987). The management of crocodilians in India, pp. 63–72. In: Webb, G.J.W., S.C. Manolis & P.J. Whitehead (eds.). Wildlife Management: Crocodiles and Alligators. Surrey Beatty and Sons Pty, Sydney.

Whitaker, R. & H.V. Andrews (2003). Crocodile conservation, aestern Asia region: An update. Journal of the Bombay Natural History Society 100: 432–445.

Whitaker, R. & Z. Whitaker (1989). Ecology of Mugger Crocodile, pp. 276–297. In: Crocodiles. Their Ecology, Management and Conservation. Crocodile Specialist Group. IUCN, Gland, Switzerland.

Wickham, H. (2009). ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York.

Woodward, A.R. & W.R. Marion (1978). An evaluation of factors affecting night-light counts of alligators. Proceedings of the Annual Conference South eastern Association Fish and Wildlife Agencies 32: 291–302.