Crocodile Lizard Research Articles

Behavioural thermoregulation by the endangered crocodile lizard (Shinisaurus crocodilurus) in captivity.

Understanding the factors that may affect behavioural thermoregulation of endangered reptiles is important for their conservation because thermoregulation determines body temperatures and in turn physiological functions of these ectotherms. Here we measured seasonal variation in operative environmental temperature (Te), body temperature (Tb), and microhabitat use of endangered crocodile lizards (Shinisaurus crocodilurus) from a captive population, within open and shaded enclosures, to understand how they respond to thermally challenging environments. Te was higher in open enclosures than in shaded enclosures. The Tb of lizards differed between the open and shaded enclosures in summer and autumn, but not in spring. In summer, crocodile lizards stayed in the water to avoid overheating, whereas in autumn, crocodile lizards perched on branches seeking optimal thermal environments. Crocodile lizards showed higher thermoregulatory effectiveness in open enclosures (with low thermal quality) than in shaded enclosures. Our study suggests that the crocodile lizard is capable of behavioural thermoregulation via microhabitat selection, although overall, it is not an effective thermoregulator. Therefore, maintaining diverse thermal environments in natural habitats for behavioural thermoregulation is an essential measure to conserve this endangered species both in the field and captivity.

Captivity Influences Gut Microbiota in Crocodile Lizards (Shinisaurus crocodilurus).

Captivity is an important measure for conservation of an endangered species, and it is becoming a hot topic in conservation biology, which integrates gut microbiota and endangered species management in captivity. As an ancient reptile, the crocodile lizard (Shinisaurus crocodilurus) is facing extreme danger of extinction, resulting in great significance to species conservation in the reserve. Thus, it is critical to understand the differences in gut microbiota composition between captive and wild populations, as it could provide fundamental information for conservative management of crocodile lizards. Here, fecal samples of crocodile lizards were collected from two wild and one captive populations with different ages (i.e., juveniles and adults) and were analyzed for microbiota composition by 16S ribosomal RNA (rRNA) gene amplicon sequencing. This study showed that the lizard gut microbiota was mainly composed of Firmicutes and Proteobacteria. The gut microbiota composition of crocodile lizard did not differ between juveniles and adults, as well as between two wild populations. Interestingly, captivity increased community richness and influenced community structures of gut microbiota in crocodile lizards, compared with wild congeners. This was indicated by higher abundances of the genera Epulopiscium and Glutamicibacter. These increases might be induced by complex integration of simple food resources or human contact in captivity. The gut microbiota functions of crocodile lizards are primarily enriched in metabolism, environmental information processing, genetic information processing, and cellular processes based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. This study provides fundamental information about the gut microbiota of crocodile lizards in wild and captive populations. In the future, exploring the relationship among diet, gut microbiota, and host health is necessary for providing animal conservation strategies.

New insights into the habitat use and husbandry of crocodile lizards (Reptilia: Shinisauridae) including the conception of new facilities for Vietnamese crocodile lizards Shinisaurus crocodilurus vietnamensis in Vietnam and Germany

The Crocodile lizard Shinisaurus crocodilurus is a popular reptile species in the pet trade and has been regularly kept in terrariums by hobbyists since the 1980s. Recent integrative taxonomic research revealed the Chinese representatives to be morphologically, genetically and ecologically distinct from Vietnamese populations, which occur in alarmingly low population sizes. All extant populations are threatened by habitat destruction and poaching for the pet trade. Thus, it will be crucial to manage the Vietnamese and Chinese subspecies separately as different conservation units, both to maintain their genetic integrity and to adjust appropriate husbandry conditions in the frame of ex situ conservation programmes. For this reason, we provide a topical review of microhabitat use of the newly described subspecies from Vietnam – the Vietnamese crocodile lizard Shinisaurus crocodilurus vietnamensis – based on recent field work as well as husbandry experiences at the Me Linh Station for Biodiversity in North Vietnam. We further compare our new findings with the data available for the nominate subspecies from China. Based on our current knowledge, we update existing minimum husbandry requirements in Germany and elaborate different husbandry parameters for both subspecies. Furthermore, we introduce new husbandry protocols and facility designs for the Vietnamese subspecies both at Me Linh Station for Biodiversity and at Cologne Zoo, Germany.

Identification of Austwickia chelonae as cause of cutaneous granuloma in endangered crocodile lizards using metataxonomics.

The crocodile lizard (Shinisaurus crocodilurus Ahl, 1930) is an endangered reptile species, and in recent years many have died from diseases, especially the rescued and breeding individuals. However, pathogens underlying these diseases are unclear. In this study, we report our effort in rapidly identifying and isolating the pathogen that causes high mortality in crocodile lizards from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve. The typical symptom is cutaneous granuloma in the infected crocodile lizards. Metagenomic next-generation sequencing (mNGS) is a comprehensive approach for sequence-based identification of pathogenic microbes. In this study, 16S rDNA based mNGS was used for rapid identification of pathogens, and microscopy and microbe isolation were used to confirm the results. Austwickia chelonae was identified to be the dominant pathogen in the granuloma using 16S rDNA based mNGS. Chinese skinks were used as an animal model to verify the pathogenicity of A. chelonae to fulfill Koch’s postulates. As expected, subcutaneous inoculation of A. chelonae induced granulomas in the healthy Chinese skinks and the A. chelonae was re-isolated from the induced granulomas. Therefore, A. chelonae was the primary pathogen that caused this high mortality disease, cutaneous granuloma, in crocodile lizards from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve. Antibiotics analysis demonstrated that A. chelonae was sensitive to cephalothin, minocycline and ampicillin, but not to kanamycin, gentamicin, streptomycin and clarithromycin, suggesting a possible treatment for the infected crocodile lizards. However, surgical resection of the nodules as early as possible was recommended. This study is the first report of pathogenic analysis in crocodile lizards and provides a reference for disease control and conservations of the endangered crocodile lizards and other reptiles. In addition, this study indicated that mNGS of lesions could be used to detect the pathogens in animals with benefits in speed and convenient.

Monitoring a loss: Detection of the semi‐aquatic crocodile lizard (Shinisaurus crocodilurus) in inaccessible habitats via environmental DNA

Abstract Assessing the conservation status of a species is strongly dependent upon data on species distribution and abundance. With the emergence of novel methods for species monitoring – such as the use of environmental DNA (eDNA) – monitoring success can be improved at reduced expenditure in the field, particularly in remote regions and terrains where access is difficult or dangerous. The highly endangered crocodile lizard (Shinisaurus crocodilurus Ahl, 1930) inhabits fragmented sites of the remaining evergreen forest with running water systems in a narrow distribution range in southern China and north‐east Vietnam. Crocodile lizards spend most of the day within or above water bodies, which are commonly remote and inaccessible. To monitor recent spatial occurrences, and to confirm the persistence or extinction of previously reported populations (especially in heavily altered habitats), the suitability of using eDNA and quantitative polymerase chain reaction (qPCR) was tested as an alternative method for monitoring this semiaquatic lizard. To assess the accuracy and limitations of this method, eDNA results from the field were compared with eDNA data from mesocosms and census data on the actual abundance of this species in the field. Environmental DNA of the crocodile lizard was detected in all of the positive controls, and in four of six natural sites; thus, all data collected using traditional field surveys were confirmed with eDNA results. eDNA monitoring was found to be a reliable method for assessing the viability of populations; we suggest that it should be developed as a tool for efficient wildlife management, particularly under difficult field and funding conditions.

Genome Sequence of Morganella morganii DG56-16, Isolated from Shinisaurus crocodilurus.

The complete genome sequence of Morganella morganii DG56-16 was sequenced. This strain was isolated from the liver of a dead crocodile lizard (Shinisaurus crocodilurus). The genome size was 3.9 Mb, with a G+C content of 50.9%.

Impacts of maternal characteristics and temperature on juvenile survival in the crocodile lizard: Implications for conservation.

Captive breeding is an important conservation measure that may restore and enhance wild populations of rare and endangered species. Multiple anthropogenic hazards have brought the crocodile lizard, Shinisaurus crocodilurus, to the brink of extinction. We initiated a captive breeding program and quantified female reproductive traits, including reproductive timing, litter size, litter mass, and neonate size. To identify the internal and external factors affecting female reproductive function, we then analyzed how maternal age is related to body size, temperature, and female reproductive traits. We found that larger female crocodile lizards produced more offspring than smaller ones, as both litter size and litter mass were positively related to maternal body size. In contrast, neonate size was independent of maternal body size. Maternal reproductive output varied among different age groups. Young and old females had significantly smaller living litter size and mass than middle-aged females. Among captive females, one-third exhibited early parturition in autumn and winter instead of the following spring, a pattern probably associated with higher ambient temperatures in captivity. Although female reproductive output and neonatal body size did not differ between early- and normal-parturition females, offspring from the former group died earlier than those from the latter. Our study highlights the danger of climate change in hastening parturition, a phenomenon that could significantly hamper neonate survival and impede population recruitment.

Complete Genome Sequence of Austwickia chelonae LK16-18, Isolated from Crocodile Lizards.

Austwickia chelonae, a species of Actinobacteria, is one of the pathogens that cause dermatophilosis in animals. Here, we report the complete genome sequence of Austwickia chelonae LK16-18, which was isolated from cutaneous granulomas in crocodile lizards.

Diets Alter the Gut Microbiome of Crocodile Lizards.

The crocodile lizard is a critically endangered reptile, and serious diseases have been found in this species in recent years, especially in captive lizards. Whether these diseases are caused by changes in the gut microbiota and the effect of captivity on disease remains to be determined. Here, we examined the relationship between the gut microbiota and diet and disease by comparing the fecal microbiota of wild lizards with those of sick and healthy lizards in captivity. The gut microbiota in wild crocodile lizards was consistently dominated by Proteobacteria (∼56.4%) and Bacteroidetes (∼19.1%). However, the abundance of Firmicutes (∼2.6%) in the intestine of the wild crocodile lizards was distinctly lower than that in other vertebrates. In addition, the wild samples from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve also had a high abundance of Deinococcus–Thermus while the wild samples from Guangxi Daguishan Crocodile Lizard National Nature Reserve had a high abundance of Tenericutes. The gut microbial community in loach-fed crocodile lizards was significantly different from the gut microbial community in the earthworm-fed and wild lizards. In addition, significant differences in specific bacteria were detected among groups. Notably, in the gut microbiota, the captive lizards fed earthworms resulted in enrichment of Fusobacterium, and the captive lizards fed loaches had higher abundances of Elizabethkingia, Halomonas, Morganella, and Salmonella, all of which are pathogens or opportunistic pathogens in human or other animals. However, there is no sufficient evidence that the gut microbiota contributes to either disease A or disease B. These results provide a reference for the conservation of endangered crocodile lizards and the first insight into the relationship between disease and the gut microbiota in lizards.

Sequencing, de novo assembling, and annotating the genome of the endangered Chinese crocodile lizard Shinisaurus crocodilurus.

The Chinese crocodile lizard, Shinisaurus crocodilurus, is the only living representative of the monotypic family Shinisauridae under the order Squamata. It is an obligate semi-aquatic, viviparous, diurnal species restricted to specific portions of mountainous locations in southwestern China and northeastern Vietnam. However, in the past several decades, this species has undergone a rapid decrease in population size due to illegal poaching and habitat disruption, making this unique reptile species endangered and listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora Appendix II since 1990. A proposal to uplist it to Appendix I was passed at the Convention on International Trade in Endangered Species of Wild Fauna and Flora Seventeenth meeting of the Conference of the Parties in 2016. To promote the conservation of this species, we sequenced the genome of a male Chinese crocodile lizard using a whole-genome shotgun strategy on the Illumina HiSeq 2000 platform. In total, we generated ∼291 Gb of raw sequencing data (×149 depth) from 13 libraries with insert sizes ranging from 250 bp to 40 kb. After filtering for polymerase chain reaction–duplicated and low-quality reads, ∼137 Gb of clean data (×70 depth) were obtained for genome assembly. We yielded a draft genome assembly with a total length of 2.24 Gb and an N50 scaffold size of 1.47 Mb. The assembled genome was predicted to contain 20 150 protein-coding genes and up to 1114 Mb (49.6%) of repetitive elements. The genomic resource of the Chinese crocodile lizard will contribute to deciphering the biology of this organism and provides an essential tool for conservation efforts. It also provides a valuable resource for future study of squamate evolution.

First crocodile-tailed lizard (Squamata: Pan-Shinisaurus) from the Paleogene of Europe

ABSTRACTCrocodile-tailed lizards are represented by a single extant species, Shinisaurus crocodilurus, the Chinese crocodile lizard, which until 2006 was completely unknown in the fossil record. These lizards may play an important role in understanding squamate phylogeny, but their biogeographic history remains murky. A new specimen from the middle Eocene of Messel, Germany, is the first record of the clade in the Paleogene of Europe. The specimen comprises an autotomized tail preserved in complete articulation. It retains a number of plesiomorphies with respect to S. crocodilurus, and it also differs from the coeval species Bahndwivici ammoskius, but comparisons with other shinisaurs are necessarily limited. The present specimen documents for the first time in the fossil record the superficially crocodile-like tail for which the extant species is named, indicating aquatic adaptation already by the middle Eocene. It furthermore raises questions about the identification of isolated ‘necrosaur’ material from the European Paleogene. Finally, it adds to growing evidence of a taxonomically similar squamate fauna in Europe and North America in the early Paleogene.Citation for this article: SMITH, K. T. 2017. First crocodile-tailed lizard (Squamata: Pan-Shinisaurus) from the Paleogene of Europe. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1313743.

Diagnostic evaluation and treatment of a Chinese crocodile lizard (Shinisaurus crocodilurus) with seizures

An 11-year-old female Chinese crocodile lizard (Shinisaurus crocodilurus) with presumed seizures was examined. Complete blood count, plasma biochemistry and MRI did not identify a cause of seizures and thus cryptogenic...

Can isotope markers differentiate between wild and captive reptile populations? A case study based on crocodile lizards (Shinisaurus crocodilurus) from Vietnam

The international wildlife trade in allegedly “captive-bred” specimens has globally increased during recent years, while the legal origin of respective animals frequently remains doubtful. Worldwide, authorities experience strong challenges to effectively control the international trade in CITES-listed species and are struggling to uncover fraudulent claims of “captive-breeding”. Forensic analytical methods are being considered as potential tools to investigate wildlife crime. The present case study is the first of its kind in reptiles that investigates the application of δ13C and δ15N stable isotope ratios to discriminate between captive and wild crocodile lizards from Vietnam. The CITES-listed crocodile lizard Shinisaurus crocodilurus is listed as endangered on the IUCN Red List mainly due to habitat loss and unsustainable exploitation for the international pet trade. Our results revealed significant differences in the composition of the two tested isotope systems between captive and wild individuals. Isotope values of skin samples from captive specimens were significantly enriched in 13C and 15N as compared to specimens from the wild. We also used the weighted k-Nearest Neighbor classifier to assign simulated samples back to their alleged place of origin and demonstrated that captive bred individuals could be distinguished with a high degree of accuracy from specimens that were not born in captivity. We conclude that isotope analysis appears to be highly attractive as a forensic tool to reduce laundering of wild caught lizards via breeding farms, but acknowledge that this potential might be limited to range restricted or ecologically specialist species.

Is there more than one Crocodile Lizard? An Integrative Taxonomic Approach Reveals Vietnamese and Chinese Shinisaurus crocodilurus Represent Separate Conservation and Taxonomic Units

The Crocodile lizard Shinisaurus crocodilurus, the only living representative of the family Shinisauridae, is a habitat specialist adapted to remote freshwater habitats within evergreen broadleaf forests. Its current distribution is restricted to few small and isolated remnant occurrences in South China and North Vietnam. Multiple anthropogenic threats such as massive habitat destruction and unsustainable over-collection for the international pet trade brought the species to the brink of extinction. We herein employed an integrative taxonomic approach including comprehensive molecular comparisons based on fragments of mitochondrial genes (cytochrome b, partial ND6, and partial tRNA-Glu) in concert with in-depth morphological and ecological analyses in order to determine the status of the extant populations. Based on molecular, morphological, and ecological differences, we herein describe a new subspecies, Shinisaurus crocodilurus vietnamensis ssp. n., from Vietnam. Our findings emphasize the importance of improved in situ conservation measures in both countries, as both China and Vietnam harbor unique Crocodile lizard forms. We also recommend additional ex situ conservation measures, i.e., separate conservation breeding management of the subspecies in order to maintain genetic integrity and adjust husbandry conditions according to detected differences in ecological niche occupation.

Building up of keeping facilities and breeding projects for frogs, newts and lizards at the Me Linh Station for Biodiversity in northern Vietnam, including improvement of housing conditions for confiscated reptiles and primates

The Me Linh Station for Biodiversity in northern Vietnam, which borders Tam Dao National Park, was established in 1999 by the Vietnam Academy of Science and Technology for the purpose of rescuing, keeping, studying and breeding Vietnamese plant and wildlife species in an in-country ex situ facility. The Institute of Ecology and Biological Resources, which runs the station, has pleased the Cologne Zoo to improve existing facilities at the Me Linh Station and to develop new ones, in particular for amphibians and reptiles, for the keeping and breeding of confiscated, endangered and selected rare or poorly known species from Vietnam for studying husbandry parameters and natural history, to build up captive assurance populations for potential future release or restocking programs, and to improve services for environmental and conservation education for visitors, school children and students. This report summarizes our joint efforts at the Me Linh Station for Biodiversity from 2012 until today. Focus is laid on the construction of indoor and outdoor amphibian facilities, but we also report about the development and buildup of crocodile lizard, monitor lizard, python and turtle enclosures, as well as of primate facilities. We also built up offspring enclosures for amphibians and reptiles, a feeder animal breeding, and created a quarantine section. Preliminary recommendations for a veterinary management are provided. Furthermore we document our joint approaches in improving the station management, developing research programmes, and report about first public awareness measures. With this article we also aim to show how facilities, breeding programs and husbandry systems can be improved and built up in a tropical country within the framework of an international cooperation.

Genetic Diversity and Population Demography of the Chinese Crocodile Lizard (Shinisaurus crocodilurus) in China

The Chinese crocodile lizard Shinisaurus crocodilurus is a critically endangered species, listed in Appendix II of CITES. Its populations and habitat in China have undergone significant changes in recent years. Understanding the genetic variability and phylogeography of this species is very important for successful conservation. In this study, samples were taken from 11 wild ponds and two captive populations in China. We sequenced mitochondrial CYTB, partial ND6, and partial tRNA-Glu and genotyped 10 microsatellite loci. Our analyses of these data showed low genetic variability, no strong isolation caused by distance, and a lack of a phylogeographic structure in this species. Based on our results, the basal divergence between two clades of S. crocodilurus in China may have been caused by the formation of the Pearl River system. We found a population expansion in one of these clades. Microsatellite analysis indicated the presence of three clusters, separated by significant genetic differences. We found that most individuals in the two captive populations were from the Luokeng (Guangdong) and Guangxi wild source populations, respectively.

Unusual Soft‐Tissue Preservation of a Crocodile Lizard (Squamata, Shinisauria) From the Green River Formation (Eocene) and Shinisaur Relationships

We describe an unusual squamate fossil from the Green River Formation (Uintan, Eocene) from the Piceance Creek Basin, Colorado, USA. The new specimen, USNM PAL 540708, is a small fossil squamate skin lacking skeletal elements. It is preserved as a part and counterpart in fine-grained limestone. Recovery of a fossil organism's skin (not a shed, but a true skin) is unusual and is most often accompanied by bone preservation. Phylogenetic analysis of a combined morphology (phenotype) and genetic data set reveals that USNM PAL 540708 is a shinisaur and reaffirms that shinisaurs are more closely related to varanids than to Xenosaurus. Shinisaur fossils are very rare, with only three species having been described (Dalinghosaurus longidigitus, Bahndwivici ammoskius, and Merkurosaurus ornatus). Despite differences in the relative size of scales, the new fossil demonstrates that shinisaurs have remained unchanged in the distribution of scales and patterns of scale size during the Cenozoic. This, paired with the osteological similarity between another Green River fossil (Bahndwivici ammoskius) demonstrates considerable overall conservatism within shinisaurs over the past 50 million years.

Granulomatous pneumonia and hepatitis associated with Providencia rettgeri infection in a crocodile monitor lizard (Varanus salvadorii)

The present report describes a case of granulomatous pneumonia and hepatitis in a male crocodile monitor lizard (Varanus salvadorii). During the necropsy of the monitor lizard, multifocal to coalescing pale yellow lesions were observed in both lung lobes, as well as similar, though milder, changes in the liver, and an ulcerative lesion on the food pad of the right hindlimb. Histopathologically, the presence of multiple necrotising, chronic granulomas containing bacterial clumps were observed in the parenchyma of the lung and the liver. By microbiological examination of the pathologically altered lung tissues, Providencia rettgeri was identified. Altogether, our findings indicate that the bacterial infection resulting in extensive chronic necrotising granulomatous inflammation was the primary cause of the reptile's death. To our knowledge, this is the first report of Providencia rettgeri-associated granulomatous pneumonia and hepatitis in the monitor lizard.

Isolation and characterization of 12 microsatellite loci in the Chinese crocodile lizard (Shinisaurus crocodilurus)

The Chinese crocodile lizard (Shinisaurus crocodilurus) is listed as one of the most endangered species in the world. There are only nine isolated populations of crocodile lizards distributed in China and one population distributed in Vietnam. 12 polymorphic microsatellite loci were isolated and characterized from a DNA library. To characterize each loci, 40 crocodile lizards individual from Guangdong province, China were genotyped. These loci showed allele numbers ranging from 11 to 20. The ranges of observed and expected heterozygosity were 0.8500–0.9750 and 0.8372–0.9347, respectively. All loci followed Hardy–Weinberg equilibrium (HWE) after Bonferroni correction. No evidence of significant linkage disequilibrium was found among any loci. Thus, we expect these markers will be useful for conservation genetic study of the Chinese crocodile lizard.

广东罗坑自然保护区鳄蜥生境选择的季节性差异

2006年3-10月,在广东省罗坑鳄蜥自然保护区利用直接观察法对鳄蜥春、夏、秋3季的生境选择进行研究。春、夏、秋3季各测定了31、71、31个有鳄蜥样方以及50、90、51个对照样方的14种生态因子。利用生态因子对比分析和逐步判别分析确定各季节生境选择的主要影响因素。结果表明,春季影响鳄蜥生境选择的主要影响因素是溪沟底质中沙的含量和植被盖度,正确判别率为97.5%;夏季影响鳄蜥生境选择的主要影响因素是溪沟底质中沙的含量、植被盖度、溪流宽度和枯枝百分比,正确判别率为94.4%;秋季影响鳄蜥生境选择的主要影响因素是溪沟底质中沙的含量、植被盖度和可利用食物量,正确判别率为97.6%。在区分春、夏、秋3季鳄蜥生境选择方面有一系列生态因子发挥作用,依照贡献值的大小依次为可利用食物量、干扰距离、枯枝百分比、溪水流速、溪沟坡度和溪宽等6个因子,由这6个变量构成的方程对春、夏、秋3季鳄蜥生境的正确区分率达到76.7%。判别函数的分析表明,春、夏、秋3季鳄蜥的生境选择具有较高的差异性,以判别函数建立的判别分类图表明,春、夏季以及夏、秋季鳄蜥的生境选择重叠较多,而秋季与春季的重叠较少。;From March to October 2006, habitat characteristics of 31, 71, 31 crocodile lizard (<em>Shinisaurus crocodilurus</em>) samples and 50, 90, 51 comparing samples (no crocodile lizard was found in these samples) were observed in Luokeng crocodile lizard Nature Reserve, Guangdong in spring, summer, and autumn respectively, to determine the main ecological factors affecting habitat selection in this species. The main ecological factors affecting crocodile lizard habitat selection in each season were determined by comparison and stepwise discriminant analysis of fourteen ecological factors measured in crocodile lizard samples and comparing samples in each of the respective seasons. Analysis showed that in spring, percentage of sand in the stream and vegetation coverage were the two main ecological factors affecting crocodile lizard habitat selection. A stepwise discriminant model including only these two factors yielded a predicted accuracy of 97.5%, the highest when compared to alternative models involving combinations of other sampled factors. In summer, percentage of sand in the stream, vegetation coverage, width of stream and percentage of dry branch were the main ecological factors affecting crocodile lizard habitat selection and the predicted accuracy of the model is 94.4%. In autumn, percentage of sand in the stream, vegetation coverage and food availability were the main ecological factors affecting crocodile lizard habitat selection and the predicted accuracy of the model is 97.6%. Habitats selected by <em>S. crocodilurus</em> in each season could be predicted with 76.7% accuracy by a model including six main ecological factors (in order of importance): food availability, distance to human disturbance, percentage of dry branch, velocity of stream water, slope of stream, and width of stream. Analysis also showed that <em>S. crocodilurus</em> spring, summer, and autumn habitats overlap to some extent, but that overlaps between spring and autumn were very low.