Venom yeld of common adder Vipera berus and steppe adder V. renardi from Volga region

The article discusses the causes and factors affecting the venom yield of common adder Vipera berus and steppe adder V. renardi. The interspecies differences in venom yield and its dependence on the size and body weight are defined. It is noted, that venom yield of females is higher than that of males, but statistically significant sex difference in venom yield of equal-sized individuals of both species are not proved.