Crotalinae

**Definition:** A subfamily of snakes commonly known as pit vipers, crotaline snakes, or pit adders in the family VIPERIDAE. They are distinguished by a deep pit called a fossa or loreal, which functions as a heat-sensing organ located between the eye and nostril on either side of the head.

**Tree numbers:** - B01.050.050.286.875.875.240 - B01.050.150.900.833.672.125.937.240 - B01.050.150.900.833.672.562.875.240

**Synonyms:** - Pit Viper - Crotalids