Toxicological Trivia from December 18, 2009: The viper pit thermoreceptors is a sensory organ, anatomically expressed in the presence of a cephalic orifice located between the nose and eye holes. The snake’s face has a pair of holes, or pits, lined with temperature sensors. The sensors indirectly detect infrared radiation by its heating effect on the skin inside the pit. The presence of this body thermoreceptors allow these animals perceive distance, the presence of mammals of which is fed from the heat radiating from their bodies. The viper pit of snakes is characteristic of the genre:
a) Bothrops;
b) Crotalus;
c) Both gender.

Correct answer: c. Crotalidae family is unique in the world that has viper pit. This family includes two genera in Argentina: Bothrops (Yarará) and Crotalus (rattlesnake). Read more with monograph in Spanish:  "Venomous Animals of Argentina. Items for recognition and first aid measures in case of accidents" (2006)