Reproductive biology of Zootoca vivipara (Reptilia, Lacertidae) in the Middle Volga region

In this article the characteristics of reproductive biology of Zootoca vivipara (Lichtenstein, 1823) from the Middle Volga region are presented. Our researching resulted that viviparous lizard of that region had earlier birth date and shorter gestation period than in other regions. The long duration of newborn being in eggshell membranes was observed in some cases. The average fecundity of viviparous lizards was statistically higher or did not differ from those of the other parts of area. Newborn of Zootoca vivipara from the Middle Volga region weighed smaller than those from populations located in the north and had smaller body length than those from northern and eastern parts of its area.