The quantities of venom injected into prey of different size by Vipera palaestinae in a single bite

The quantity of venom injected by a snake is one of the most important factors determining the danger of the bite. The present study tests whether the amount injected is in correlation with the size of the prey. Seven specimens of Vipera palaestinae injected with 14 C‐amino acids in order to label the venom, were offered three pairs of one mouse and one rat each. The amounts of venom injected into either prey were variable, ranging from zero to more than 200 mg. In most cases 50 mg were injected, approximately 8% of the total venom available in the glands. In three snakes the average amount injected into rats was two to three times higher than that injected into mice; in two snakes the mice received three to ten times more than the rats, while in two snakes there was no difference between the amounts injected into either prey. It is concluded that the size of the prey does not necessarily influence the amount of venom injected by the snake.