Common lizard (c) Tom Aspinall
The common lizard (Zootoca vivipara) is a widespread species, present throughout the UK and the Community Science project area.
Adult common lizards usually emerge from hibernation in March, with males typically emerging a few weeks before females. Adults mate in April or May and females give birth to 3-11 live young in July or August. Females incubate eggs internally and give birth to live young, a strategy that is uncommon amongst reptiles.
The common lizard is, therefore, sometimes called the viviparous lizard; viviparous meaning bearing live young as opposed to laying eggs. Individuals spend the autumn feeding up in preparation for hibernation. Their main prey items are spiders, insects, snails and earthworms. They hibernate from around November to March, often in communal groups amongst rocks or dead wood.
Common lizards are found in heathlands, moorlands, grasslands and woodlands (as well as on dry stone walls, railway/road embankments, derelict urban sites and sea cliffs). In spring they bask in sunny, dry, open places such as stones, logs or grass tussocks to absorb heat from the sun. They tend to bask where there is dense cover nearby, as they like to shelter beneath logs and stones when startled, as well as at night. They are preyed upon by birds including crows, jays and hawks as well as foxes, domestic cats and other reptiles. Common lizards can shed their tail as a defence mechanism when they are attacked. A replacement tail is often grown but this is shorter, more stubby and darker than the original.
Numbers of common lizards have declined in the UK in recent years. Threats come from habitat loss, a decline in quality of habitat and habitat fragmentation. In Great Britain, common lizards are protected by law: it is illegal to deliberately kill, injure or sell wild common lizards.
- Common lizards can be up to 15cm long, including their tail.
- They have scaly skin which is variable in colour between individuals but usually brown/grey with rows of darker markings on their back and sides. Individuals can, however, be yellow, green or even black and have no additional markings.
- Males have bright yellow or orange undersides with black spots whereas females have a paler white, yellow, grey or greenish underside, usually with no spots.
- Juvenile common lizards are less than 5cm long and are very dark in colour.
Common lizards could be confused with newts, but lizards move rapidly when disturbed whereas newts usually hide under logs and in thick grass during the day and are unlikely to move if disturbed.
Lizards also have scaly skin whereas newts have smooth or warty looking skin. Of the other native reptile species in the UK, sand lizards are only found in restricted locations in southern England and the coast around Merseyside and north and west Wales; and slow worms do not have legs.
Why we’re interested
Common lizards are expected to suffer reductions in their distribution as the climate changes. This species is expected to suffer losses in southern and eastern England, but if future greenhouse gas emissions are high, losses could extend throughout most of Wales and central and northern England as well as lowland areas of Scotland. In these circumstances, the South Pennines could become a refugia (a geographically isolated “safe haven” surrounded by unsuitable habitat) for the common lizard.
Records submitted to this survey will help track whether the distribution of the common lizard is changing over time.
Research has also shown that in years with warmer summer temperatures, the common lizard tends to give birth to young earlier in the year. Records collected in this survey will also be used to track whether the timing of events, such as emergence from hibernation and breeding, are changing and whether this is linked to changes in climatic conditions.
Further information about lizards and climate can be found in 'Climate change modelling of English amphibians and reptiles: Report to Amphibian and Reptile Conservation Trust (ARC-Trust)'.