The Device

Vipers belong to the snake group with tube teeth (Solenoglypha), whose poison device distinguishes itself by its great mobility and flexibility. When the mouth is shut or only slightly open the poison teeth are pointing backwards. Only when the mouth opens and upper and lower jaw bones are spread widely apart the extraordinary flexibility of various bones enable the teeth to unfold to the front. Apart from injecting a usually lethal mixture into the prey the teeth have the additional function to facilitate swallowing the prey: When vipers have found their food or have the killed animal in their mouth they use the flexibility of their poison teeth by alternately gripping the prey in the front first with one and then with the other tooth, pulling it into their bodies bit by bit.




	The open mouth of a Desert Horned Viper (cerastes cerastes). The poison theeth embedded in the skin folds are clearly visible. This animal has an additional side tooth. During examinations of Gaboon adder up to 5 additonal side teeth have been counted – contrary to the information in the relevant specialized literature!


	Rhinoceros viper (bitis nasicornis) swallowing its prey. One can see clearly how at that moment the left poison tooth is pushed forward to use it like a hook.


	By “folding back” the tooth the captured animal is pulled into the mouth. This process is repeated alternately with the right and the left poison tooth.

Always ready …

Vipers renew their poison teeth at regular intervals. At least one side tooth is continuously growing and presses the respective active tooth forward until it breaks off. The opposite picture shows two teeth of a Bitis Gabonica Gabonica found in an interval of app. 6 months. During this period the approximately 2-year-old snake had only negligibly grown in size and girth. The poison teeth however have adapted in shape and length to the changed skull size.


	Copyright: Chris Mattison “Die Schlangen Enzyklopädie” , by “blv” 1999