Head to head
Common Wall Lizard vs Viviparous Lizard
Across much of Europe these two small lizards can turn up in the same region, and in Britain both occur, though only one is native. The common wall lizard and the common, or viviparous, lizard differ in body shape, in where they live, and above all in how they reproduce.
| Common Wall Lizard | Viviparous Lizard | |
|---|---|---|
| Scientific name | Podarcis muralis | Zootoca vivipara |
| Body shape | Slim, flattened, long-tailed, fast | Stockier, shorter-tailed |
| Eggs or live young | Lays eggs, up to three clutches a year | Gives birth to live young in most of its range |
| Habitat | Walls, rocks, ruins, quarries, railway banks | Heath, moor, bog, rough grassland, wood edges |
| In Britain | Introduced and local | Native and widespread |
| Male belly | Whitish or pinkish, blue outer scales | Orange with dark spots |
| Range | Central and southern Europe, plus introductions | The widest of any lizard, into the Arctic |
| Climate | Heat-loving; active on mild winter days | Cold-hardy; furthest north of any reptile |
Wall Lizard vs Common Lizard: common questions
How do I tell a wall lizard from a common lizard?
Look at the body and where the animal is. A wall lizard is noticeably flattened, slim, and long in the tail, moves in fast bursts, and is almost always on or near vertical stone, a wall, a rockery, a ruin, or a railway embankment, often several metres up. A common lizard is rounder-bodied and shorter-tailed, moves in shorter dashes between low cover, and is found on the ground among heather, tussocks, logs, and bog vegetation rather than on walls. Colour overlaps, but a greenish or rusty wash and pale blue spots along the edge of the belly point to a wall lizard, while an orange spotted belly on a male points to a common lizard. In Britain, a lizard on an old town or coastal wall in the south is likely an introduced wall lizard, and a lizard on a heath almost anywhere is the native common lizard.
Why does one lay eggs and the other give birth to live young?
It reflects the climates the two species evolved in. The wall lizard is a warmth-loving animal of central and southern Europe, where the ground gets hot enough in summer to incubate a buried clutch of eggs, so it lays eggs in the standard reptile way. The common lizard lives across a colder and shorter-summered range, reaching the far north of Europe and high into the mountains, where eggs left in the ground would often fail to develop before winter. Its solution is to keep the developing eggs inside the female's body, where she can warm them by basking and move them into shelter, and then give birth to fully formed young. Interestingly, a few common lizard populations in the warm south of its range still lay eggs, which makes the species a natural experiment in the evolution of live birth.
Is the wall lizard a problem where it has been introduced?
It can be, locally. The common wall lizard establishes readily from a small number of released or escaped animals, and colonies are now scattered across southern England and elsewhere well outside its natural range, as well as the large population around Cincinnati in the United States. Where it takes hold on walls, banks, and rocky ground it is very successful, and there is evidence that in some places it competes with and displaces the native common lizard, which uses similar basking spots and prey. It does not threaten the wall lizard's own conservation status, which is secure, but its spread is watched with some concern by conservationists precisely because of the pressure it can put on native reptiles.