Rattlesnakes are highly adept at following substrate chemosensory trails left by struck (envenomated) prey. However, there are other sources of chemical information that may be present in the post-strike environment, such as odors from unstruck mice, that could either confound or aid predatory success. Rattlesnakes can follow airborne chemosensory trails of a struck prey, but the ability of rattlesnakes to use airborne chemosensory cues of unstruck prey has not been examined. Therefore, our purpose was to examine the abilities of rattlesnakes to locate prey using substrate and airborne cues from unstruck mice and compare this with their success with airborne odors from struck mice. We used a Plexiglas Y-maze through which paired airborne and/or substrate odor choices were presented to northern Pacific rattlesnakes (Crotalus oreganus). In one treatment, snakes given a choice of odor from an unstruck mouse (substrate) versus a control (unscented air) showed a significant preference for the unstruck, substrate odor trail. In a second treatment, snakes given a choice of unstruck mouse odor (airborne) versus a control (unscented air) showed no significant preference for the airborne odor. In a third treatment, snakes given a choice of unstruck mouse (airborne) versus struck mouse odor (airborne) again showed no preference for either odor. This last result suggests that one cue used during airborne trailing is a general chemical cue and is most likely not associated with a distinct post-strike searching image (as is the case in substrate trailing). Snakes also exhibited certain behaviors within the maze (i.e., turning behavior, emergences) more often when exposed to airborne cues than when exposed to substrate cues. These observations indicate that a different system of behaviors is used when rattlesnakes follow airborne compared to substrate odor cues during post-strike trailing.

Time spent pursuing, capturing, and subduing prey, and time spent preparing and swallowing it all affect profitability of a prey item (net energy gain/handling time). In the diet selection model of classical optimal foraging theory, handling time is constant for each prey type, but several factors affect it in some predators. We studied factors that might cause time spent to capture and handle prey by broad-headed skinks (Eumeces laticeps) to vary between and within prey types. Pursuit time did not vary with prey (cricket) size in experimental conditions. In three experiments using crickets of the same size, handling times for the first prey eaten were shorter when more prey were simultaneously present. Reduced handling time likely maximizes number of prey captured before the remaining prey escape. Preparation time (capture to initiation of swallowing) did not vary with prey number, but swallowing time decreased with number of prey present. This result suggests that lizards must prepare crickets thoroughly for digestion by bites puncturing the exoskeleton, which constrains them from decreasing preparation time. However, lizards can reduce handling time by swallowing more quickly, increasing the likelihood of capturing additional prey. Handling times were shortest for hungry skinks and longest just before satiation. Two factors may contribute to the increase in handling time with degree of satiation: (1) Motivation to capture prey declines as a predator becomes satiated, removing the reason for shortening handling times when groups of prey are present; (2) as the stomach and the esophagus are filled, mechanical constraints may slow swallowing. Preparation time, number of bites, swallowing time, and handling time increased with cricket size. Consequently, although it appears that the largest prey were the most profitable for sizes of crickets studied, this may not be true for other ranges of prey size. Preparation time was shorter for prey bitten on the head than on the side or back, but prey orientation during swallowing did not affect swallowing time. In summary, (1) when prey are present simultaneously, total energetic profit may be increased by reducing handling time, and (2) handling for specific prey types vary with satiation and handling method.

We studied the composition and richness of local tadpole assemblages in several streams at a forest site in southeastern Brazil. We initially focused on species distributions within streams, comparing the relative availability of microhabitats with the relative use of each microhabitat type by tadpoles of different species, in order to assess the existence of preference patterns. Then we assessed the role of features assumed to influence species distributions among streams, which may influence breeding site selection by adult frogs and, consequently, tadpole distribution. These features were stream size, tadpole predator abundance, structure of marginal vegetation, and microhabitat availability for tadpoles. We looked for gradients of species richness along gradients of the variables noticed to influence tadpole assemblage composition. Tadpoles of all species showed selectivity in microhabitat use. Species distribution among streams was influenced mostly by number of potential tadpole predators present, stream volume, arboreal vegetation cover at stream margins, and tadpole microhabitat diversity, though only the first two variables accounted for gradients in species richness. Even though smaller streams tend to shelter more anuran species than larger ones at sites in southeastern Brazil, we recommend the conservation of streams of a range of sizes and structural features, since anuran assemblages associated with streams vary in species composition along gradients in these characteristics.

The Flint Hills of Kansas and Oklahoma are the largest remaining tracts of tallgrass prairie in North America. This area has undergone major changes in land management practices in the past 30 years. Traditional season-long cattle stocking with variable burn schedules has diversified to include intensive-early cattle stocking accompanied by annual burning. To understand how different land management practices affect the herpetofauna of a tallgrass prairie, we used mark-recapture statistics to analyze herpetofaunal community dynamics. We analyzed survey data collected over a 15-year time span (1989–2003) from a rangeland site in Cowley County, KS, USA. A modified Jolly-Seber open population model, POPAN-5, was used to estimate four community parameters: probability of species loss (φ;′), probability of detection (P), probability of entry (P_ent), and species richness (N). The top models included burn status as a covariate for species loss rate, while cattle stocking received moderate support as a covariate. Rates of species loss were higher during burn years (φ;′  =  0.04, 95% CI: 0.02 to 0.08) than nonburn years (φ;′  =  0.00, 95% CI: 0.00 to 0.01). Analysis of the impacts of different management practices was difficult due to confounding effects of changes in both burning and grazing. Declines in species richness tended to be steepest during a period of season-long stocking, but results were not statistically significant. Though our limited data set does not allow us to draw strong conclusions on the effects of land management on herpetofaunal populations, the mark-recapture models illustrated in our study should prove to be a valuable tool in future analyses of similar data.

Both abiotic factors and behavioral patterns may influence snake activity. However, other than reproductive activities, behavioral patterns have rarely been incorporated into studies of snake habitat selection. We investigated seasonal differences in canebrake rattlesnake (Crotalus horridus) movement patterns and habitat selection. We modeled habitat selection in two ways, with and without regard to behaviorally-based seasons, and compared the two models to determine which yielded the most informative results. Behaviorally-based seasons (foraging, breeding, and hibernation) were determined from field observations of study animals. Habitat selection was modeled as habitat use versus availability using a case control sampling design for males and nongravid females using logistic regression. Males had significantly larger home ranges, moved more often, and traveled greater distances between successive locations during the breeding season as compared to nongravid females. The male no-season habitat model lacked significance, and the nongravid female no-season model revealed a positive association with pine savannas. When behaviorally-based seasons were included in the models, both sexes showed distinct seasonal variation in habitat selection, with males and nongravid females using similar habitat for breeding and hibernation, but partitioning habitat during the foraging season. Our results indicate that behaviorally-based seasons provide important details about intraspecific canebrake rattlesnake habitat selection and movement patterns, and that future research should benefit from the inclusion of snake behavior in habitat studies.

Breeding behavior of individuals can play an important role in the success of an invasive event. I studied the breeding behavior of the Cuban treefrog Osteopilus septentrionalis, an invasive anuran species endemic to Cuba, but accidentally introduced to Puerto Rico and other countries. Breeding events lasted only one night, the sex ratio was male-biased, and male mating behavior changed from acoustic competition to scramble searching over the breeding event. Most of the males had similar opportunities to mate with a large or small female. Males did not defend territories and did not exhibit parental care. Males of any size could fertilize most eggs of any female, although larger females produced more eggs than smaller females. Thus, there were no direct adaptive benefits for high mating selectivity by females. This absence of high selectivity by females can increase the invasive capacity of O. septentrionalis because it can reduce the strength of Allee effect (fitness reduction in small population primarily to the difficult of finding mates).

Reproduction in a population of painted dragons, Ctenophorus pictus (Agamidae), in semi-arid South Australia was studied over two years with distinctly contrasting climatic conditions. Data were collected from wild lizards to assess the influence of inter- and intra-seasonal conditions on reproductive characters of the small, short-lived lizard during a very wet year and a season with average rainfall. Females began to develop ova at the end of winter (August) and laid eggs during the spring and early summer, coinciding with the period of testicular enlargement in males. Potentially four, or possibly more, clutches of 2 to 4 eggs (mean 2.6) were produced by females each year. Egg moisture content varied considerably and ranged between 45 and 79% (mean 66%) of total egg mass. Eggs contained less moisture in the wet year (1992–93). Females containing oviducal eggs were marginally larger in the wet year of 1992–93 than in 1991–92. Eggs collected late in the reproductive season were significantly larger than those collected earlier. A ‘parental investment’ model can be used to explain this intra-seasonal shift in egg size. When adjustments for female size were made, reproductive investment was consistent between the two years of the study, with no difference in egg mass, clutch mass or clutch size detected. The reproductive strategy of C. pictus remained remarkably invariant considering the dramatic difference in climatic conditions between the two years of the study.

Cnemidophorus longicauda is a poorly-studied species of whiptail lizard distributed in the Monte Desert region of Argentina. Some variation in dorsal color pattern has been observed between northern and southern populations along the latitudinal range of the species. Recently, a new species of Cnemidophorus (C. tergolaevigatus) previously considered as C. longicauda has been described, although no comparative morphological study has been conducted. In this study we use the mitochondrial ND4 gene region to examine the phylogeography and genetic structure of this species complex. Phylogenetic reconstruction, Nested Clade Phylogeographic Analysis, and AMOVA reveal deep genetic divergence between northern and southern populations that are geographically separated by the Famatina–Sañogasta Mountains. Because most of the localities of C. tergolaevigatus are from the general region of the “northern group” recovered in this study, there is general concordance between geographic patterns of mtDNA and morphological (color pattern) variation, and thus support for the recognition of this species. We discuss this genetic break and the phylogenetic/phylogeographic history of the Cnemidophorus in the context of other lizard species with similar distributions, and the implications for understanding the evolutionary history of the temperate South American biota.

I present a phylogeny of the Latin American snake genus Chironius based on 36 external morphological and hemipenal characters. Data from the literature for the 20 recognized species of Chironius were combined with data I collected from 20 outgroup taxa. I assessed the monophyly and in-group relationships of Chironius using both parsimony and methods. Two optimal trees were obtained using parsimony criteria; the genus Chironius is supported as monophyletic with 93% bootstrap support from six unambiguous synapomorphies, including an even number of scale rows at midbody. A Bayesian analysis of the data supports the monophyly of Chironius with a posterior probability of 100%. Both analyses inferred similar topologies; recognized species groups are partially supported, but this analysis suggests that revision of the genus is necessary. I propose elevation to full species status of taxa within the carinatus, fuscus, multiventris, and quadricarinatus species groups on the basis of morphological features unique to each taxon. Future molecular work is necessary to resolve the remaining taxonomic issues within Chironius.

A new species of treefrog is described from Chapada Diamantina in the central State of Bahia, Brazil. The new species is a member of the Bokermannohyla pseudopseudis group, characterized by its small to medium size, head as long as wide, snout short, rounded in dorsal view and nearly truncate in lateral view, eyes and tympanum large, and forearm and prepollex well developed. The new species can be distinguished from the other species of the B. pseudopseudis group by its voice and the shape of its head and snout. It is smaller than B. saxicola and B. pseudopseudis, and has a less developed forearm and prepollex than B. ibitiguara males. The tadpole and vocalizations are described and information on natural history is provided.

A new, lowland species of Ansonia is described from the Endau-Rompin National Park in southern peninsular Malaysia based on having a unique eye color and dual vocal slits, as well as a unique combination of head, body, digit, and color pattern characteristics. This new species is the southernmost member of the genus in continental Asia and emphasizes the importance for additional field work in southern Malaysia.