Pit vipers can strike and kill their prey with extreme accuracy even after they have been blindfolded.  The viper's infra-red sensing organs have been attributed as the cause of that.  However, the pit organ on each side of their face has been credited to the level of accuracy with which the vipers hit their target. Providing a blurry picture of the objects around them, these pit organs or "holes" are supposed to work as pin-hole cameras. What provides the final details of the snake's potential prey, allowing them to create a graphic, mental image of the animal around them, are the heat sensors situated within the membranes. Scientists created a model that mimicked the functionalities of the snake's pit organ which resulted in surprisingly accurate results.

 

Source : Spider