Viviparous lizard  (Zootoca vivipara)

The viviparous lizard is classified as Least Concern (LC) on the IUCN Red List (1) and is listed under Annex III of the Bern Convention (3) (4).

The viviparous or common lizard (Zootoca vivipara) is extremely variable in colour. Typically, the upperparts of the lizard are brownish with lines of darker markings passing along the back, which are often bordered with white or yellow. Individuals may occasionally have green, grey or reddish upperparts, which can cause problems with identification (2).

The male viviparous lizard has a bright underside, typically yellow or orange in colour, but more rarely red with black spots. In contrast, the female viviparous lizard tends to have much duller, paler underparts. Totally black forms occasionally arise in both sexes. In addition to the differences in belly colour, the male lizard can also be distinguished from the female by its much larger head, slender body, and by the possession of a prominent swelling at the base of the tail (2).

The viviparous lizard has one of the widest ranges of any vertebrate. It is found throughout central and northern Europe, including Britain and Ireland, eastwards to the Pacific coast, from Sakhalin Island, Russia, to Hokkaido, Japan. It occurs as far south as the Mediterranean, and is the most northerly of all reptiles, inhabiting Scandinavia and Arctic Russia (2) (5).

Several subspecies have been described, and the viviparous lizard is likely to be a species complex that should be split into a number of separate species (1).

The viviparous lizard is found in a variety of habitats, and prefers open, sunny areas. It tends to occur in dry areas, but also frequents wet heaths, although its main habitats include commons, moorland, heaths, sea cliffs, dry stone walls and embankments. The viviparous lizard even occurs in tundra (2) (6).

This species is a cold-blooded (poikilothermic) reptile, and it must invest much of its time in basking in the sun, particularly during early spring and late autumn (before and after hibernation). When it first emerges in the morning, the body temperature of the viviparous lizard is typically around 15 degrees Celsius; however, this species’ optimum body temperature is 30 degrees Celsius, which is attained through basking and absorbing heat from the sun. Basking also occurs throughout the summer, when the lizard needs to warm itself up sufficiently in order to hunt, particularly on overcast or cool summer days (2).

As a result of its extremely large geographical distribution and the wide range of different habitats and climates it inhabits, the viviparous lizard is not currently considered to be threatened (1).

However, some populations of this species are declining due to habitat loss, particularly as a result of agricultural intensification, urbanisation and tourism development (1).

The viviparous lizard is listed on Annex II of the Bern Convention (4) and Annex IV of the European Union Habitat and Species Directive (7), both of which aim to protect wild flora and fauna and their natural habitats. This species also occurs in numerous protected areas across its range (1).

The viviparous lizard is protected by national legislation in most of its range countries, and in Britain it is listed under Schedule 5 of the Wildlife and Countryside Act (1981), protecting it against killing, injury and sale (8).

View information on this species at the UNEP World Conservation Monitoring Centre.

For more on this species and other reptiles and amphibians found in the UK:

• Herpetological Conservation Trust:
  http://www.herpconstrust.org.uk/