What specialized sensory organ defines a pit viper?
Answer
Loreal pits
The loreal pits are the highly specialized sensory organs located on the face between the eye and the nostril that give pit vipers their common name and allow for infrared detection.

Related Questions
What specialized sensory organ defines a pit viper?Where are the loreal pits anatomically situated on the head of a pit viper?What mechanism describes the hinged fang structure characteristic of pit vipers?What is the primary chemical characteristic of typical pit viper venom?To which scientific subfamily do pit vipers belong?The loreal pit allows pit vipers to perceive which type of radiation emitted by prey?Which non-pit viper snakes generally rely solely on sight and smell for hunting?What is the primary prey type suggested by the evolution of the loreal pit organ?Which of the following groups is NOT listed among the major pit viper groups residing heavily in the Americas?When a pit viper's mouth is closed, what happens to its solenoglyphous fangs?