Morphological and physiological changes during reproduction and their relationships to reproductive performance in a capital breeder.

Current reproductive effort typically comes at a cost to future reproductive value by altering somatic function (e.g., growth or self-maintenance).

Morphological and biochemical analyses of original and regenerated lizard tails reveal variation in protein and lipid composition.

Caudal autotomy, or voluntary self-amputation of the tail, is a common and effective predator evasion mechanism used by most lizard species. The tail contributes to a multitude of biological functions such as locomotion, energetics, and social interactions, and thus there are often costs associated with autotomy. Notably, relatively little is known regarding bioenergetic costs of caudal autotomy in lizards, though key morphological differences exist between the original and regenerated tail that could alter the biochemistry and energetics.

Sexual variation in assimilation efficiency: its link to phenotype and potential role in sexual dimorphism.

Sex-specific variation in morphology (sexual dimorphism) is a prevalent phenomenon among animals, and both dietary intake and resource allocation strategies influence sexually dimorphic traits (e.g., body size or composition).

Water supplementation affects the behavioral and physiological ecology of Gila monsters (Heloderma suspectum) in the Sonoran Desert.

In desert species, seasonal peaks in animal activity often correspond with times of higher rainfall. However, the underlying reason for such seasonality can be hard to discern because the rainy season is often associated with shifts in temperature as well as water and food availability. We used a combination of the natural climate pattern of the Sonoran Desert and periodic water supplementation to determine the extent to which water intake influenced both the behavioral ecology and the physiological ecology of a long-lived desert lizard, the Gila monster (Heloderma suspectum) (Cope 1869).

Water storage compromises walking endurance in an active forager: evidence of a trade-off between osmoregulation and locomotor performance.

Trade-offs between locomotor performance and load-carrying in animals are well-established and often result from requisite life processes including reproduction and feeding. Osmoregulation, another necessary process, may involve storage of fluid in the urinary bladder of some species. The purpose of this study was to determine whether storage of urine in the urinary bladder reduces walking endurance in an actively foraging lizard.

The urinary bladder as a physiological reservoir that moderates dehydration in a large desert lizard, the Gila monster Heloderma suspectum.

Animals inhabiting xeric environments use a variety of behavioral and physiological strategies to balance water budgets. We studied the potential contribution of the urinary bladder to osmoregulation in a large desert lizard, the Gila monster Heloderma suspectum. Here we present results of a series of in vivo laboratory experiments which tested the hypothesis that the Gila monster urinary bladder serves as a physiological reservoir, as in amphibians and chelonians, providing water that buffers increases in plasma osmolality when food and water are unavailable.