Concealed weapons: erectile claws in African frogs

Concealed weapons: erectile claws in African frogs.

Vertebrate claws are used in a variety of important behaviours and are typically composed of a keratinous sheath overlying the terminal phalanx of a digit. Keratinous claws, however, are rare in living amphibians; their microstructure and other features indicate that they probably originated independently from those in amniotes. Here we show that certain African frogs have a different type of c...

Terahertz imaging of subjects with concealed weapons

In response to the growing interest in developing terahertz imaging systems for concealed weapons detection, the Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts Lowell has produced full-body terahertz imagery using coherent active radar measurement techniques. The proof-of-principle results were readily obtained utilizing the compact radar range resources at ST...

Venomous Frogs Use Heads as Weapons

Venomous animals have toxins associated with delivery mechanisms that can introduce the toxins into another animal. Although most amphibian species produce or sequester noxious or toxic secretions in the granular glands of the skin to use as antipredator mechanisms, amphibians have been considered poisonous rather than venomous because delivery mechanisms are absent. The skin secretions of two ...

Female African Clawed Frogs Androgen-Induced Vocal Transformation in Adult

Evolution of advertisement calls in African clawed frogs.

For most frogs, advertisement calls are essential for reproductive success, conveying information on species identity, male quality, sexual state and location. While the evolutionary divergence of call characters has been examined in a number of species, the relative impacts of genetic drift or natural and sexual selection remain unclear. Insights into the evolutionary trajectory of vocal signa...