This particular image offers an excellent view of the juvenile coloration of the distal tail tip, which is a bright yellow, disappearing when the snake reaches its adult status. The adult A. contortrix pit viper grows to a length 50cm to 95cm, and is pictured in PHIL 8130 and 10841. The name “pit viper” is derived from the fact that these snakes possess two heat-sensing organs situated inside a pit on either side of its head between each ipsilateral eye and nostril, both of which are visible from an anterolateral perspective in PHIL 10843, 10848, and 10849.