Above, the real deal; below, the clay models used to test predators' reactions to local and foreign frog markings. Sometimes, you have to make a thousand frogs from modelling clay to make your point.

Natural selection has played a role in the development of the many skins patterns of the tiny Ranitomeya imitator poison dart frog, according to a study that will be published in an upcoming edition ...

Poison ivy, poison oak, and poison sumac all contain urushiol, a toxic oil that triggers an allergic rash in most people 12 to 72 hours after contact. Urushiol can spread from contaminated clothing, ...