C.M. Gienger

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• NA at Austin Peay State University

We tested the hypothesis that helodermatid lizards (Gila monsters, Heloderma suspectum Cope, 1869, and beaded lizards, H. horridum (Wiegmann, 1829)) show sexual dimorphism in morphological traits related to malemale agonistic behaviors. Malemale combat in helodermatid lizards involves repeated sequences of ritualized grappling. Male Gila monsters u...

Hibernacula play an important role in the ecology of high-latitude snakes, and communally denning species may occupy their hibernacula for half the year or more. Because of the long duration spent at hibernacula, such sites can provide multiple benefits to snakes including shelter from lethal overwinter conditions, social opportunities, and basking...

Informamos sobre interacciones ecológicas entre el monstruo de Gila (Heloderma suspectum) y la tortuga del desierto (Gopherus agassizii) en el desierto de Mojave del sur de Nevada. Los huevos de la tortuga del desierto son una fuente importante de alimento para los monstruos de Gila, y aunque las tortugas no siempre tienen éxito, defienden vigorosa...

During the course of a telemetry study on three species of Australian frogs (Litoria caerulea, Litoria dahlii and Cyclorana australis), we found that many of the surgically implanted transmitters had migrated into the bladder. We subsequently implanted small beads into L. caerulea and they were expelled from the body in 10-23 days. Beads implanted...

Describing future habitat for sensitive species can be helpful in planning conservation efforts to ensure species persistence under new climatic conditions. The Gila monster (Heloderma suspectum) is an iconic lizard of the southwestern United States. The northernmost range of Gila monsters is the Mojave Desert, an area experiencing rapid human popu...

Host–parasite relationships are important components of ecological systems that influence the evolution of both hosts and parasites. High levels of ectoparasitic infections can disrupt host homeostasis, causing adverse effects on health and performance. However, the effects of natural ectoparasite levels on host physiology are less understood, with...

For animals exhibiting range residency, the home range is a useful framework to quantify space use. Some reptiles can live decades in the wild and experience extreme environmental variation that influences patterns of habitat use. Individuals may modify their use of space over time, reducing the utility of single‐year home range estimates. Very hig...

Contemporary plant communities are simultaneously the reflection of current habitat conditions and historic processes. The observed patterns in the diversity, abundance, and composition of these communities are the result of the combination of stochastic and deterministic factors. Deterministic factors such as environmental filters often leverage a...

In oviparous reptiles, parental care is often limited to the energy allocated to embryos before oviposition. Reproducing females can allocate energy toward vitellogenesis, determining the number and size of eggs, fertilization, eggshell calcification, retention of eggs within the oviduct after fertilization (oviductal egg retention), and nesting ac...

The influence of environment and phylogeny on morphological characteristics of organisms is well documented. However, little is known about how these factors influence scale shape in fishes, a feature which may be important for drag reduction. We evaluated the impact of both on scale shape variation in the primarily benthic, riverine darter clade (...

Intensification and expansion of agriculture is one of the most pressing concerns for biodiversity conservation. Amphibian and reptile communities can be particularly sensitive to land-use change; therefore, understanding how land use and agricultural practices influence these communities in areas under increasing agricultural pressure is prudent....

Trait specialization often comes at the expense of original trait function, potentially causing evolutionary tradeoffs that may render specialist populations vulnerable to extinction. However, many specialized adaptations evolve repeatedly, suggesting selection favors specialization in specific environments. Some garter snake (Thamnophis) populatio...

In this note, we document the use of repeatedly burned habitat by an uncommon salamander species.

Variation in animal responses to feeding can be attributed to a variety of ecological factors, including foraging mode and dietary specialization. Specialization often favors species that have traits for exploiting food resources that are rare and that are not commonly shared by dietary generalists. We investigated physiological and behavioral resp...

Fire can alter habitats available to wildlife through modification of structural and micro-climatic characteristics. Because of their reliance on behavioral thermoregulation and crypsis, reptiles can be especially influenced by fire-induced habitat alterations. Copperheads (Agkistrodon contortrix) are a widely distributed snake species found throug...

Landscape disturbances can alter habitat structure and resource availability, often inducing physiological responses by organisms to cope with the changing conditions. Quantifying the endocrine stress response through measurement of glucocorticoids has become an increasingly common method for determining how organisms physiologically respond to cha...

Fire can have diverse effects on ecosystems, including direct effects through injury and mortality and indirect effects through changes to available resources within the environment. Changes in vegetation structure such as a decrease in canopy cover or an increase in herbaceous cover from prescribed fire can increase availability of preferred micro...

Attributing biological explanations to observed ecogeographical and ecological patterns requires eliminating potential statistical and sampling artifacts as alternative explanations of the observed patterns. Here, we assess the role of sample size, statistical power, and geographic inclusivity on the general validity and statistical significance of...

Phenotypic plasticity can occur in response to environmental fluctuation and can bring about pronounced changes in behavioral, physiological, or morphological traits. Anthropogenic habitat modifications, such as prescribed fire, can provide insight on the phenotypic response of ectotherms to structural habitat change. Our objective was to quantify...

Knowledge of species-specific patterns of energy use is important for understanding the evolution of life histories as well as for determining how species might respond to alterations in environmental conditions. We measured standard metabolic rates (SMRs) in 59 Eastern Box Turtles (mass range=106-510 g) and determined how differences in body mass...

Handling venomous snakes can be a dangerous endeavour and the safety of both the handler and the snake should be a priority at all times. We here present our design of a series of plexiglass shields to protect the handler during the process of transferring snakes between cages, transfer containers, or experimental enclosures in the lab. We found th...

Context In Queensland, the management of estuarine crocodiles (Crocodylus porosus) by the government is important for ensuring public safety, especially along the populated east coast, where there is a large human population. Aims The present study aimed to determine historical, temporal and spatial patterns of human–crocodile conflict in Queensla...

Due in part to their large size, aggressive temperament, and difficulty in handling, there are few physiological studies of adult crocodilians in the literature. As a result, studies comparing individuals across an ontogenetic series and comparisons among species are also lacking. We addressed this gap in knowledge by measuring standard metabolic r...

Raw data used to calculate standard metabolism in three species of crocodilians. (XLSX)

Pathogens that cause subclinical diseases or exhibit low infection intensities are difficult to quantify in wild populations. Mojave desert tortoises ( Gopherus agassizii ) have been the focus of much research aimed at measuring the presence of upper respiratory disease (URTD) and URTD-associated pathogens, and techniques used to quantify disease i...

We report on a survey of the small mammal communities of Anaho Island and the mainland surrounding Pyramid Lake in the Great Basin of western Nevada. Ten rodent species were detected on the mainland, but only the deer mouse (Peromyscus maniculatus) was detected on Anaho Island. Although the mean abundance of deer mice on the Pyramid Lake mainland w...

Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Al...

•We tested the ‘fighting hypothesis’ using data from the Ultimate Fighting Championship (UFC).•This hypothesis posits that human left-handedness is maintained via advantages in male–male combat.•Previous research found equivocal support for this hypothesis.•In our analysis, left-handed fighters reached the UFC more easily but had no advantage once...

Field metabolic rates (FMR) and water influx rates (WIR) were measured in Gila Monsters (Heloderma suspectum) in the Mojave Desert of southern Nevada. Gila Monsters had rates of energy use that were less than half of those expected for lizards of their size, including species that live in arid habitats. Free-living Gila Monsters also had comparativ...

Patterns of body size evolution on islands provide compelling cases of rapid and dramatic phenotypic evolution in terrestrial vertebrates, yet debate remains over the relative roles of predation and resource availability in driving such evolution. We compared the morphology of five reptile species (four lizards, one snake) from Anaho Island, a dese...

Standard metabolic rate (SMR, ml O(2) min(-1)) of captive Crocodylus porosus at 30 °C scales with body mass (kg) according to the equation, SMR = 1.01 M(0.829), in animals ranging in body mass of 3.3 orders of magnitude (0.19-389 kg). The exponent is significantly higher than 0.75, so does not conform to quarter-power scaling theory, but rather is...

We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24 h of feeding, a postfeeding metabolic peak (peak ZO12018_E1a.gifO2) of 1.4–2.0 times SMR, and a...

Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our understanding of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of wh...

Among the limited reports on reproduction on free-ranging helodermatid lizards (genus Heloderma; Gila Monsters and Beaded lizards) there are reports that hatching and emergence from nest cavities of Beaded Lizards, Heloderma horridum, occurs coincident with the onset of summer monsoon rains (Beck 2005). H. horridum is restricted to the tropical dec...

A number of environmental variables have been identified as affecting anuran color, but rarely have the interactions between these variables been investigated. In attempt to elucidate the function of color change, we conducted a within-subject, full factorial experiment designed to determine the simple and interactive effects of background, tempera...