Chinese Giant Salamanders (Andrias davidianus) have experienced an 80% population decline since the 1950s. Captive salamander farms in China might provide a source population for reintroduction projects involving this species. To provide recommendations on rearing individuals for reintroduction, we studied the effect of water temperature on the growth of captive-reared juvenile (2–6 yr) A. davidianus and compared their body condition with wild specimens. We reared 240 salamanders in two groups, exposed them to different water temperatures for 7 mo, and monitored their growth over the next 3 yr. Subjects that were exposed to lower water temperatures (0.8–19.4°C) were lighter and shorter than those maintained at higher temperatures (7.8–19.1°C). Furthermore, subjects maintained at lower temperatures had a lower growth rate than those maintained at higher temperatures, except for the interval between the last two measurements. Captive-reared salamanders had lower body-condition indices than wild animals having the same body length during the study period. Captive subjects were 16% and 19% lighter than wild individuals of the same length when maintained in the high- and low- temperature groups, respectively. Our study indicates that water temperature affected juvenile growth, and captive-reared A. davidianus older than 5 yr had a body-condition index approaching that of individuals in the wild.

Predation is a key determinant of pond community structure, yet not all predators are equally effective and not all life stages of potential prey are similarly susceptible. Understanding the effects of native and introduced species is essential to informing management strategies, especially for endemic and species of conservation concern. We examined the effects of five common predators (three native: Central Newts [Notophthalmus viridescens louisianensis], aeshnid dragonfly naiads [Aeshnidae], and Southern Leopard Frog tadpoles [Lithobates sphenocephalus]; and two introduced: Fathead Minnows [Pimephales promelas] and Mosquitofish [Gambusia affinis]) on survival of eggs and recently hatched larvae of Ringed Salamanders (Ambystoma annulatum). We also examined the effect of supplemental food or cover availability on survival at each stage. Predators primarily showed a binary response to eggs, consuming all or none of them. Supplemental food did not influence whether eggs or larvae were consumed. Larvae were consumed by all predator species although the effect varied. The presence of cover did not reduce the impacts of the other predators on larval survival. Overall, the two introduced fish species had a greater impact on survival of the early stages of Ringed Salamanders than did the native predators. Further inquiries into the susceptibility of different life stages and survival will improve conservation strategies for rare and endemic species such as Ringed Salamanders.

Western Painted Turtles (Chrysemys picta bellii) are the most anoxia-tolerant tetrapods known, capable of surviving anaerobically at 3°C for nearly 5 mo. In the northernmost latitudes of their range, adult painted turtles can experience winters lasting 6–7 mo. During this time, the pond surface is covered with ice and snow, denying the turtles access to air and trapping them in water that can become severely hypoxic or anoxic. Previous studies have reported that turtles overwinter near the bottom of ponds, either buried in mud or on top of the substrate, where oxygen levels are hypoxic or anoxic. The oxygen is depleted by other respiring biomass within the mud, but why the turtles are found on or within it is not understood. To better understand the overwintering behavior of painted turtles, we conducted a series of laboratory experiments to determine how a turtle's buoyancy is affected by temperature, depth, and access to air. Acclimating turtles to 3°C resulted in a large variation in turtle buoyancy, but preventing access to air caused all turtles to become negatively buoyant. We suggest that painted turtles overwinter in the mud or on the pond bottom not necessarily because of any particular behavioral adaptation, but simply because they become negatively buoyant while overwintering without access to air.

Little information on the behavioral ecology and social organization of New Zealand's diplodactylid geckos is available. At least two species may be gregarious and share shelters, but data on the extent and possible function of this behavior are lacking. We examined the spatial distribution patterns of Duvaucel's Geckos in diurnal retreats over the four seasons. We tested whether geckos formed aggregations more often than expected by chance, and investigated whether or not the thermal properties of used shelters, gecko body temperatures and group composition affected aggregation patterns. Duvaucel's Geckos utilized a range of natural structures as diurnal shelters and showed a tendency to aggregate throughout the year (47–71% of individuals). Mixed-sex groups of up to eight individuals, including juveniles, occurred year round. Aggregations never contained more than one adult male and typically consisted of a male–female pair. Shelter-sharing adult males were larger than solitary males. Juveniles sheltered in close association with adults of either sex throughout the study. Shelter thermal properties did not appear to influence aggregative behavior. Aggregation patterns fluctuated seasonally, but the factors affecting these distribution patterns remain unclear. The occurrence of year-round shelter aggregations and frequent male–female and adult–juvenile associations indicate that this species might possess a complex social system. Further research examining the social and genetic relationships between group members, juvenile dispersal rates, and the temporal stability of aggregations is required to confirm the degree of complexity.

Few extensive studies have addressed the ecology of South American colubrids. Spilotes pullatus is a large and conspicuous colubrid snake with a broad distribution in South America. We analyzed the morphology, habitat use, diet, feeding behavior, and reproductive biology of S. pullatus in a subtropical area of distribution, specifically in the Atlantic Forest of southeastern Brazil. We compared its ecological traits with those of other South American colubrids to identify common characteristics and differences among these snakes. Spilotes pullatus inhabits primarily lowland areas and readily occurs in altered habitats. Male and female snakes were similar in median snout–vent length, but the largest known individuals of the species are males. This snake forages actively by day, searching primarily for small mammals and nestling birds (usually 0.36–7.37% of snake mass) on the ground or in vegetation. Observations of captive snakes showed that small prey are quickly swallowed alive, whereas large prey are constricted or pressed against the substrate and die before swallowing. The reproductive cycle of the females appears to be seasonal, with vitellogenesis occurring from the middle of the dry season to the onset of the rainy season. Mating was recorded at the end of the dry season and the onset of the rainy season and coincided with the onset of male–male combat. Such combat behavior includes partial entwining of the anterior portions of the body and a consistent, upright position of the trunk. Recruitment of newborns occurs at the end of the rainy season and during the dry season. Spilotes pullatus shows unique characteristics but also shares several ecological traits with other South American colubrids.

Establishing and monitoring population trends is essential for implementing informed and timely management decisions and also for the conservation of threatened species. We examined changes in Nile Crocodile (Crocodylus niloticus) population size and changes in the size–class distribution within the population using aerial and ground survey data from 1971–2009 in the Ndumo Game Reserve (NGR), South Africa. In addition, crocodiles were caught opportunistically for aging, sexing, and tagging. Precision and accuracy of population estimates were affected by water level, season, and the use of different observers. Future surveys should occur in austral winter and at low water levels. The NGR population increased from an absolute abundance of 348 (±3.4; an estimate of precision based on 1 SE) in the early 1970s to maximum absolute abundance of 992 (±58.7) in 1994 as a result of a restocking program initiated in the late 1960s and early 1970s. The population structure is currently skewed towards subadults and adults and the current population is in decline. This is a result of low recruitment levels in NGR, which are unable to sustain the artificially high population size created by the restocking program. Also contributing to this decline is the poaching of crocodiles and destruction of suitable and historical nest sites. Sex ratios were skewed toward females in juveniles and subadults and toward males in adults, while the overall sex ratio in the population was even. The current NGR Nile Crocodile population is estimated at an absolute abundance of 846 (±263). We predict that the NGR Nile Crocodile population will continue to decline in the future as part of the natural process, but the decline will be accelerated on account of poaching, uncontrolled harvesting, and destruction of nesting habitat.

Distribution patterns reflect the interactions of organisms with their environment. We discuss the distribution patterns of Nile Crocodiles (Crocodylus niloticus) in a naturally patchy floodplain environment with the use of aerial survey data collected over the last 40 yr. Although only 10,000 ha in size, Ndumo Game Reserve (NGR) supports one of the largest wild crocodile populations in South Africa, largely because of landscape complementation with neighboring Mozambique. Distributions within the NGR were influenced by landscape physiognomy and composition as well as connectivity and corridor quality. To quantify the effects of environmental conditions on crocodile distribution, we conducted 40 diurnal counts at Lake Nyamithi in the NGR between 2009 and 2012. Average monthly maximum temperature had an effect on the number of crocodiles in Lake Nyamithi; however, environmental variables influenced different size classes of Nile Crocodiles to a varying extent. Anthropogenic disturbances influenced the functionality of the floodplain landscape negatively, with impacts on habitat use and connectivity. It is considered essential that a cross-border conservation program be initiated in order to conserve the current population of Nile Crocodiles in the greater NGR area.

The reproduction of Saltwater Crocodiles (Crocodylus porosus) is seasonal, coinciding with the wet season (October–May) in the Northern Territory, Australia. Understanding environmental factors influencing the population dynamics of C. porosus can have important implications for the management of this species. We examined the relationship between hatchling density and monthly rainfall in the preceding wet season using crocodile population data from standardized spotlight surveys in 10 tidal rivers from 1976 to 2012 and historical weather data. Hatchling densities in four rivers were negatively correlated with monthly rainfall around the peak of the wet season (January or February). Hatchling densities in four rivers were positively correlated with rainfall after the peak months. Hatchling densities in eight rivers were positively correlated with rainfall after the wet season peak (April or May). Our results support previous observations that: (1) the length of the wet season determines the extent of reproduction; and (2) flooding caused by heavy rains in the middle of the wet season leads to higher rates of egg mortality. These relationships could be used to estimate reproductive success from year to year, and to guide management decisions such as adjusting the harvest intensity of eggs and hatchlings.

We describe the morphology of the digestive tube of Podocnemis expansa, Podocnemis unifilis, Podocnemis sextuberculata, Podocnemis erythrocephala, and Peltocephalus dumerilianus. The esophagus in these species has two distinct regions: the anterior region has esophageal papillae and the posterior has longitudinal folds. Esophageal glands are absent but goblet cells occur in the mucosa of esophagus. The stomach in P. expansa, P. unifilis, and P. erythrocephala has two regions: the anterior region consists of cardiac and fundic regions and is without glands; the more-posterior pyloric region contains gastric glands that extend into the lamina propria. In P. sextuberculata, the stomach is a J-shape, and in Peltocephalus dumerilianus the stomach is a C-shape with a larger curvature to the left side. The stomachs of these two species have numerous gastric glands in all regions. The small intestine (SI) in all species is a long, coiled tube and has folds and villi that appear different in each region. In P. expansa, P. unifilis, and P. erythrocephala, there is a dilatation in the anterior region of large intestine (LI), followed by a straight and tubular region of smaller diameter. In P. sextuberculata and Peltocephalus dumerilianus, the dilatation is absent and the LI is tubular and of uniform diameter along its entire length. The LI has a larger quantity of goblet cells than the SI. The digestive tube of the turtles in the family Podocnemididae demonstrates differences in the morphology between species, and these differences could be related to the diet of each species.

Foi descrito a tubo digestório de Podocnemis expansa, P. unifilis, P. erythrocephala e Peltocephalus dumerilianus. O esôfago das espécies analisadas apresenta duas regiões distintas: a região anterior com presença de papilas esofágicas e a região posterior com pregas longitudinais. Glândulas esofágicas foram ausentes, mas células caliciformes ocorreram na mucosa do esôfago. O estômago em P. expansa, P. unifilis, e P. erythrocephala apresenta duas regiões: a região anterior que é formada pelas regiões cárdica e fúndica e é ausente de glândulas; e a região posterior, considerada a região pilórica, com glândulas gástricas em sua lâmina própria. Em P. sextuberculata o estômago teve forma de “J” e em Peltocephalus o estômago tem formato de “C” com a curvatura maior do lado esquerdo. O estômago dessas espécies apresenta numerosas glândulas gástricas em todas as regiões. O intestino delgado em todas as espécies é um tubo longo e enovelado e com pregas e vilosidades que se diferenciam em cada região. O Em P. expansa, P. unifilis, e P. erythrocephala, existe uma dilatação na região anterior do intestino grosso (IG), seguindo de uma região retilínea e tubular de menor diâmetro. Em P. sextuberculata e Peltocephalus, a dilatação é ausente, o IG segue como órgão tubular de di

Phenotypic variation can be expected among individuals of a species having a broad geographic distribution because genetic uniqueness can be exaggerated by adaptation to local environmental conditions. Paralaudakia caucasia is a widely distributed agamid species in the western Palearctic that occupies a region from Pakistan to the Lesser Caucasus. To describe the geographic variation in this taxon from Pakistan to the Lesser Caucasus, we examined 49 male P. caucasia from three regions in Iran (western Elburz, central Elburz, and eastern Elburz) and one in Pakistan. Twenty-five morphometric and meristic characters were examined using analyses of variance and principal components analysis. Of the measured characters, 21 were different among these populations. The differences among males representing the four groups indicate that these groups exhibit geographic variation corresponding to differences in environmental conditions from east to west. We suggest that future studies using more material from differentiated populations across the entire range will better elucidate how the environment has shaped this species' morphology.