The viviparous lizard, or common lizard, is a Eurasian lizard. It lives farther north than any other species of non-marine reptile, and is named for the fact that it is viviparous, meaning it gives birth to live young. Both "Zootoca" and "vivipara" mean "live birth", in (Latinized) Greek and Latin respectively. It was called Lacerta vivipara until the genus Lacerta was split into nine genera in 2007 by Arnold, Arribas & Carranza.

Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to reproduce. By contrast, interspecific competition occurs when members of different species compete for a shared resource. Members of the same species have rather similar requirements for resources, whereas different species have a smaller contested resource overlap, resulting in intraspecific competition generally being a stronger force than interspecific competition.