It is now well documented that androgen and estrogen signaling dur- ing early development cause a sexual dimorphism in second-to-fourth digit length ratio (2D:4D). It is also well documented that males of mam- malian ...

Digit length ratios are organized during embryonic development and may show sexual dimorphism related to steroid exposure. The second-to-fourth digit length ratio (2D:4D) has received the most attention. In the present ...

The Palo Verde wetland, one of the most important places for aquatic organisms in Costa Rica, is currently recovering from an invasive expansion of Typha domingensis (cattail). A monitoring program was designed to understand ...

Offspring discrimination, the differential treatment of offspring and unrelated young, functions in numerous animal taxa to ensure that vital and costly parental care behaviours are appropriately directed. Discrimination ...

Aposematic coloration allows predators to use visual cues to avoid eating potentially toxic or distasteful prey. Predators across many animal taxa actively avoid aposematically colored prey and remember distasteful brightly ...

Despite the benefit of the tympanic middle ear to airborne hearing sensitivity, anurans range in how soon they develop functional middle ears after transitioning to life on land. Previous evi- dence suggested that bufonids ...

Clay models have been used to investigate the relative antipredator effectiveness of cryptic and of aposematic coloration in litter frogs, but such studies do not account for possible differences in prey escape behavior. ...

In June 2014, we captured approximately 100 R. dorsalis tadpoles in a net from a seasonal wetland in Palo Verde National Park (10.3428 N, 85.3375 W) in N, 85.3375 W) in northwestern Costa Rica. While rearing the tadpoles ...

Rhinella yunga, a recently described toad species of the Rhinella margaritifera group (Moravec et al. 2014. Zookeys 37:35–56), is known from the tropical mountains of the Cordillera Yanachaga, Junin Province, Peru. Rhinella ...

In recent decades, theoretical and empirical work has investigated the relative roles of costs and benefits in inhibiting excessive displays of begging to parents. Whether costs are important in maintaining reliability of ...