The loreal pit is the deep depression, or fossa, in the loreal area on either side of the head in

pit viper The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfa ...

s (crotaline snakes). The area is located behind the nostril and in front of the eye, but below the line that runs between the centers of each. It is the external opening to an extremely sensitive infrared detecting organ. The loreal pit is bordered by

lacunal scales Lacunal scales are those scales that form the inner border of the loreal pit The loreal pit is the deep depression, or fossa, in the loreal area on either side of the head in pit viper The Crotalinae, commonly known as pit vipers,Mehrten ...

. The loreal pit also functions as part of a thermal regulating system, enabling pit vipers to maintain their body temperature.

References

Snake anatomy {{snake-stub