Nikhil Whitaker - Academia.edu (original) (raw)

Papers by Nikhil Whitaker

Journal of Threatened Taxa, 2022

A study was conducted to examine the population estimate and spatial distribution of Mugger Croco... more 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 f...

Behaviour, 2022

Animals modulate their behaviours in accordance with their local environment and in the process, ... more Animals modulate their behaviours in accordance with their local environment and in the process, undergo different behavioural and physiological adaptations to better survive in a given ecosystem. One such behaviour that plays an important role in survival and sustenance of a species is the breeding behaviour. In this article, we present anecdotal information on breeding strategies of Marsh or Mugger crocodiles. Mugger crocodiles mostly lay single clutch during a year and have an elongated courtship and mating period lasting for 3–4 months. However, we show anecdotal data covering a period of 2 years for a Mugger crocodile producing double clutches annually under captive conditions. The laying of multiple clutches in captive Mugger crocodiles may indicate higher nutritional status and/or breeding strategies of the females under resourceful conditions. We suggest the need for future work on understanding proximate mechanisms underlying the ‘double clutching’ behaviour of Mugger croco...

Reptiles & Amphibians, 2022

Russian Journal of Herpetology, 2011

Between April 2001 and February 2003, ecdysis of snakes in captive population of Ophiophagus hann... more Between April 2001 and February 2003, ecdysis of snakes in captive population of Ophiophagus hannah was studied. A strong relationship was observed between snake total length and slough length, resulting in a regression equation that may be used to predict total length from slough length. The number of sloughs per snake increased with total feed weight, and average monthly feed weight. Inter-slough periods differed between sexes, with females shedding at wider intervals at an average of 63.27 days, and males at 55.77 days. In a year, males shed at an average of 6.0 times, while females averaged 5.2 times. Cumulative difference in inter-sloughing periods between the fifth and sixth year of age were significant, averaging 59.54 days at the former age, and 61.65 at the later. No relationship was observed between either average minimum temperature or maximum temperature and the number of snakes sloughing a month. Rainfall did not influence the number of snakes that shed in a given month...

International Journal of Fisheries and Aquatic Studies, 2020

Conflict between humans and crocodiles on the Cauvery river delta region is discussed. Four insta... more Conflict between humans and crocodiles on the Cauvery river delta region is discussed. Four instances of situations were recorded, namely attacks on people (fatal and non-fatal), the capture of crocodiles from nearby inhabited areas, translocation of crocodiles to other areas of the River, and crocodiles entering human habitation. Distances between translocation sites and non fatal attacks averaged 10.12 Km, whilst distance between fatal attacks averaged 58.73 Km.

International Journal of Health, Animal science and Food safety, 2018

The Indian subcontinent is incredibly rich in biodiversity and is home to many species of herpeto... more The Indian subcontinent is incredibly rich in biodiversity and is home to many species of herpetological and conservation interest. The aim of this study was to provide a first assessment of hematological values in Travancore tortoise ( Indotestudo travancorica ) and red-crowned roofed turtle ( Batagur kachuga ), two endangered species on which medical literature is still lacking. Between May and June, 19 specimens of I. travancorica and 17 of B. kachuga were sampled. Both populations were housed by the Madras Crocodile Bank Trust – Centre for Herpetology (Tamil Nadu, India). From each animal, a blood sample (0.5 mL) was obtained from the dorsal coccygeal vein and stored in a lithium-heparin test tube. Regarding I. travancorica , from each sample was performed a complete red and white blood cell count (RBC and WBC) with the Natt & Herrik method using a Neubauer chamber, and hematocrit values were assessed using microcapillaries. Mean Corpuscular Volume (MCV) was calculated from PCV ...

Contemporary Herpetology, 2006

Reproductive biology of Aspideretes gangeticus was studied between 1986 and 2001. Clutchsize aver... more Reproductive biology of Aspideretes gangeticus was studied between 1986 and 2001. Clutchsize averaged 17.9 eggs and ranged between six to thirty-fi ve eggs. Egg length averaged 30.6 mm,egg width averaged 30.22 mm, and egg weight averaged 16.85 g. Clutch volume averaged 253.75ml. No signifi cant difference was observed in clutch size between dry and wet seasons. Of the variousincubation protocols tested, one that involved transitional temperatures of 28º – 31º C, to chilling at15º – 18º C, and then 23º – 26º C resulted in the highest hatching success. Aspideretes gangeticusexhibit two forms of development arrest during incubation, embryonic diapause early in incubation andembryonic aestivation in the latter trimester of incubation. The two Aspideretes gangeticus femalesthat produced clutches for the current study produced eggs with a high fertility percentage throughoutthe fi fteen years for which they stored sperm.

Journal of Zoo and Wildlife Medicine, 2000

Crocodylians being poikilotherms, are of interest because of their massive sizes, and how they re... more Crocodylians being poikilotherms, are of interest because of their massive sizes, and how they respond to situations where behavioural thermal selection varies. The purpose of this study was to examine Tb trends in Crocodylus palustris, with respect to post-feeding, the impact of enclosure maintenance, how visitor numbers affected Tb, and variability within and between animals. The three subject animals comprised a group of 31 crocodiles, held in a natural pond. Hobo TM loggers were used to record deep body temperatures, which were inserted surgically into the peritoneal cavity of ten females. Prior to this, all animals were measured, weighed, and codes recorded. Crocodiles maintained a very narrow regime in temperature chosen, and rainfall did not result in an increase in Tb; minor increases in Tb were observed post-feeding, a decrease in Tb was observed on the Park's day off. A major maintenance activity resulting in elevated Tbs for up to a week in all animals. Despite large deviations in female weight, Tb remained similar. Oscillation in Tb was similar, lower thresholds being at 0700 hrs, and peaking at 1700hrs.

We analysed 159 distress calls of five individuals of T. schlegelii for temporal parameters and o... more We analysed 159 distress calls of five individuals of T. schlegelii for temporal parameters and obtained spectral parameters in 137 of these calls. Analyses of G. gangeticus were based on 39 distress calls of three individuals, of which all could be analysed for temporal and spectral parameters. Our results document differences in the call structure of both species. Distress calls of T. schlegelii show numerous harmonics, whereas extensive pulse trains are present in G. gangeticus. In the latter, longer call durations and longer intervals between calls resulted in lower call repetition rates. Dominant frequencies of T. schlegelii are higher than in G. gangeticus. T. schlegelii specimens showed a negative correlation of increasing body size with decreasing dominant frequencies. Distress call durations increased with body size. T. schlegelii distress calls share only minor structural features with distress calls of G. gangeticus.

Molecular Ecology Resources, 2010

Illegal hunting has been a major threat for the survival of wildlife fauna, including the three c... more Illegal hunting has been a major threat for the survival of wildlife fauna, including the three crocodile species that India harbours: Crocodylus palustris, Crocodylus porosus and Gavialis gangeticus. Although law prevents trade on these species, illicit hunting for trade continues to threaten the survival of these endangered species; conservation strategies therefore require a rapid molecular identification technique for Indian crocodiles. A multiplex polymerase chain reaction (PCR) assay with species-specific primers, considered as one of the most effective molecular techniques, is described herein. The primers were designed to yield species-specific sized amplicons. The assay discriminates the three Indian crocodile species unambiguously within a short time period using only simple agarose gel electrophoresis. We recommend this multiplex PCR assay to be used in the identification of Indian crocodile species.

Chelonian Conservation and Biology, 2009

A 2-year study was conducted on the forest cane turtle, Vijayachelys silvatica, in Chalakudy Dist... more A 2-year study was conducted on the forest cane turtle, Vijayachelys silvatica, in Chalakudy District, Kerala, South India. This is a poorly known species, endemic to the Western Ghats of Southern India. The aims of the study were to ascertain morphometrics, sex ratios, and ...

Morphometrics, 2012

The most threatened chelonians occur in Asia, where virtually all species are heavily harvested f... more The most threatened chelonians occur in Asia, where virtually all species are heavily harvested for food and traditional medicinal trades (van Dijk et al. 2000). This includes the two endemic chelonians, Indotestudo travancorica, and the sympatric Vijayachelys silvatica in the Region of the Western Ghats, South India. Indotestudo travincorica is listed as Vulnerable under the IUCN Red List, and comes under Schedule IV of the Indian Wildlife (Protection) Act. Phylogenetic relationships between the three species of Indotestudo, these being forstenii, elongata, and travancorica, have been in flux. Iverson et al (2001) examined these clades, and found that I.travancorica, the species in question here, was found to be more closely related to I. elongata. They also place Indotestudo forstenii from Sulawesi and Halmahera, as a distinct species unrelated to I.travancorica and I. elongata, refuting information that I. forstenii were introduced from India to Indonesia.

International Journal of Current Microbiology and Applied Sciences

Conference Presentations by Nikhil Whitaker