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 ...

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 ...

Aggression between nurserymates is common in animals and often hypothesized to result from proximate resource limita- tion. In numerous terrestrial frogs, larvae develop in phytotelmata, tiny water bodies where resources ...

Many organisms use chemical defenses to reduce predation risk. Aposematic dendrobatid frogs sequester alkaloid-based chemical defenses from a diet of arthropods, but research on these defenses has been limited to adults. ...

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 ...

Parents defend their young in many ways, including provisioning chemical defences. Recent work in a poison frog system offers the first example of an animal that provisions its young with alkaloids after hatching or birth ...

What are poison frogs? Poison frogs, also commonly called ‘dart poison frogs’ or ‘poison arrow frogs’, are charismatic amphibians forming a spectacular adaptive radiation, comparable to that of African cichlids. Many of ...

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 ...