|Common name:||common wall lizard|
|Taxonomy:||Podarcis muralis (Linnaeus, 1758)|
|Other Names:||Wall lizard|
European wall lizard
This very agile lizard is well named as it can often be seen basking, hanging from walls or rock faces. It is either green or brown with mottled marking along its flanks, and reaches a length of about 8-inches (20cm) with the tail making up to two thirds its overall length.
In the British Isles in particular, this lizard is associated with man-made habitats; particularly stone walls such as old houses, boundary features and castles. It can also be found on cliff faces, and strongly favours south facing faï¿½ades.
There has been some discussion as to whether the Wall lizard is a native species, as it is on Jersey in the Channel Islands. Although it cannot be ruled out with complete certainty, All scientific evidence (including legacy records, museum specimens, zooarchaeological remains & DNA analysis) suggest that the Wall lizard is an entirely introduced species to the United Kingdom, with many documented releases across the nineteenth century.
The Wall lizard is very agile, and uniquely for British reptiles, can be seen running up vertical surfaces such as rock-faces or walls. It grows to around 20cm (8 inches) in length, with the tail making up around two-thirds of its overall body length.
There are two forms of Wall lizard within the UK: the brown-backed form which originated from western continental Europe (predominantly from Brittany, France), and the green-backed form which originates from Italy.
Both forms exhibit a mottled pattern along the flanks, often with black and white reticulations and an occasional blue scale along the edge of the black and white mottled belly.
Compared to native lizards, the eyes are set high on the head, and the snout is set high and rounded, resembling a small alligator
Telling the sexes apart can be difficult, however the male has a larger head and a thick-set neck. Sometimes the banding along the flanks of the female is more noticeable than that of the male. Females are often significantly smaller than the male.
Could be mistaken for
Common_lizard.jpg,Wall_Lizard_vs_Sand Lizard.jpg,Wall_Lizard_vs_Green Lizard.jpg
There are around twenty separate colonies of the Wall lizard within the UK. These colonies are for the most part isolated and reasonably well self-containing. All these colonies are either associated with human habitation, such as Ventnor on the Isle of Wight, or with South-facing sea cliffs, such as most of the Dorset colonies.
The only native populations within the British isles are on the Channel island of Jersey. All introduced colonies are within England, with the overwhelming majority located in the South of the country.
The wall lizard is naturally saxicolous (lives amongst rocks), however in the UK The wall lizard is particularly associated with man-made habitats, where it takes advantage of worked stone of walls and buildings. This lizard is also well adapted for cliff faces and quarries.
It needs wall cavities in which to shelter, but also loose stones at ground-level, under which the lizard lays its eggs. Some vegetation is required to support the food chain of invertebrates, but too much vegetation does not suit this lizard as it is a lover of sunshine and requires open bare areas.
Old stone garden walls are a particularly favourite habitat, although the wall must have a mix of vegetated portions and open basking spots. There should also be good vegetation at ground level to help to support the food chain.
All habitat locations within England are south-facing with long hours of sunlight, and are predominantly in the south of England.
The Wall lizard is a diurnal animal, and a lover of strong sunshine. It has only the loosest concept of hibernation, and can be seen basking on bright sunny days, even in December and January.
Similarly, it disobeys the usual concept of a mating season, with two, three or even four clutches of eggs being laid across the year.
The wall lizard is adept at catching all sorts of invertebrates, with particular favourites being crickets and grasshoppers, spiders, caterpillars and woodlice.
It will eat flying insects such as flies, moths and butterflies, and can often be seen athletically jumping to attempt to catch a passing meal.
When prey is caught, the lizard will thrash the item from side to side to subdue its meal, before eating the animal, head first, then carefully wiping its jaws along the ground to remove any remaining legs or antennae.
Unlike our native lizards, the Wall lizard will also eat fruit and berries even including strawberry jam!
The wall lizard is subject to predation from a wide range of animals. On cliff faces, kestrels can be seen plucking them from their basking sites, while those colonies based upon human habitations are at more risk from the domestic cat. Locals on the Dorset cliffs have seen Brown rats digging up the lizard's eggs.
The wall lizard will make use of any dry, frost-free refuge, although it has a strong preference for cracks and voids in stone; whether this is in an old stone wall, a cliff face or paving slabs.
If stone is unavailable, it will redily make use of any hollows found in debris or rubble.
It is an accomplished digger, and will readily burrow if no natural shelter is available.
In colonies with dense populations, males can exist without individual territories; however, where territories are defended; fights between rival males are not uncommon. Disputes are sometimes settled by posturing, followed by a short chase; however, if equal males meet, fights can occur. The lizards attempt to grasp each other by mouth, often locking jaws. The animals are totally preoccupied and can be approached readily. Once dominance is established, the victor will chase the loser for a distance of around ten metres, before returning to defend his prime location.
There is little courtship associated with mating. The male will approach a female, and if receptive, the male will grasp the female using his jaws, and manoeuvre his grip until he is grabbing the mid-body of the female. Copulation lasts for only a few seconds, after which the female is released, accompanied by her immediately dashing for cover.
The first clutch of eggs are usually laid in March, and are either buried in the ground, or placed under thin flat rocks such that the warmth of the sun can reach the eggs. Between 3 and 17 eggs are laid (usually around 8), which take around a month to develop into new-born and independent hatchlings. In urban areas, a favoured laying place is in hollows beneath paving slabs.
Juvenile wall lizards have similar markings as adults, but are of course much smaller. Compared with adult lizards, juveniles' heads appear to be proportionately larger.
Prey items for juveniles are the same as for adults, but with smaller specimens being caught.
The lizards can reach sexual maturity before the age of three years, which coupled with their multiple clutch-laying can result in the animals out breeding native competitors.
Although the Common wall lizard is a European protected species, as an introduced species to the United Kingdom it has no legal protection. The native colonies on Jersey (not a part of the United Kingdom) are protected.
The main conservation issue concerning the Wall lizard is its impact upon native species. To date, no detrimental effect has been proven, however anecdotal evidence suggests that the high breeding rates and agility, and hence its ability to catch prey items can cause a decline in native species. Most colonies of wall lizards within the UK are isolated and self contained by suitable habitat. The main area of concern, is where their distribution overlaps that of native legged lizards, as is the case with the Bournemouth cliffs. Since the introduction of Wall lizards on these cliffs, the numbers of Common lizards, and the rare Sand lizard have declined. There may be additional factors causing this decline, however the impact of the Wall lizards should not be discounted.
A further cause for concern is the possible transmission of pathogens to native animals. It is unlikely that released Wall lizards have been properly screened for disease, and it is possible that natural pathogens could cause harm to native species.