The viviparous lizard (Zootoca vivipara) has spread further north than any other lizard, occurring as far north as Lapland and the Arctic Ocean. It favours open places, rocks, beaches, piles of logs and building walls. They can often be seen on duckboards, sometimes even in small groups.
Viviparous lizards mate in May and their young are born in late July. The female incubates its eggs inside itself, by lounging out in the sun. It gives birth to between five and ten young, which are initially surrounded by egg membranes, from which they break free within a day. Giving birth to live young is unusual among reptiles. The trait is an adaptation to the northern climate, one that is also possessed by the European adder.