If you’ve spent any time outdoors in France during spring or summer, you’ve likely noticed small shapes darting across sun-warmed walls or disappearing into hedgerows as you approach. These shy creatures are your local lizards, and they’re far more fascinating than their fleeting appearances might suggest. We spoke with lizard expert Roger Meek, a long-time resident of the Vendée, to learn more about the species we share our gardens with.

Meet Your Most Common Neighbors: Wall and Green Lizards

Here in western France, the species we see most frequently are the wall lizard, Podarcis muralis, and the western green lizard, Lacerta bilineata. Both are members of the Lacertidae, a large family of lizards with more than 300 species across Europe, Africa and Asia. Lacertidae are sometimes referred to as ‘true lizards’ due to their generalised lizard shape and their lack of elaborate frills or crests.

Of the two, the most common species is the wall lizard which you can find in many different types of habitats including suburban areas and woodland edges. They have a foraging lifestyle, actively searching for small bugs including grasshoppers and spiders, but they may also consume berries and fallen fruit. Reaching a length of around 70mm (not including their tail), as their name suggests, they are often seen basking in the sun on walls or rocks. Wall lizards show substantial colour variation and patterns, but the females are usually grey or brown while males are generally more colourful and often have a mottled pattern.

Females in western France produce two clutches of eggs each year, the first during spring followed by a second in mid-summer, while in southern Europe three annual clutches are the norm. In the Vendée, we typically see around 5 eggs per clutch.

The Social Lives of Wall Lizards

Wall lizards are mainly active during the warmer months, particularly in spring. They normally enter a winter dormant period in October or November appearing again in February, although during the winter of 2021/22 activity was recorded on sunny days throughout the winter months in the Vendée. Some internet sources indicate they are a solitary species but during spring and autumn they are highly social and can be seen communally sun-basking in groups including a single male and several females. However, alpha males do not tolerate other males and will patrol and defend a territory, although beta (lower ranking) males will often live close by and occupy the ‘optimum’ territory should it be apparent that the alpha male is no longer present.

The Stunning Western Green Lizard

Green lizards are less commonly seen. Lacerta bilineata is one of several species in the green lizard group including the eastern European form Lacerta viridis, which is very similar to the western species. There is also a giant form, Lacerta trilineata, that occurs in the Balkans. The western green lizard reaches a body length of around 120mm, not including its tail, and is one of the world’s most beautiful lizards.

In fragmented landscapes as we have locally, green lizards are mostly found in hedgerows and sometimes in light urban areas. They operate as ambush predators, remaining motionless while waiting for the prey to come into range, then quickly pouncing. They emerge later from hibernation than wall lizards, usually in late March or early April, and also enter their winter dens earlier, usually during October.

They are highly territorial and normally only make contact with other green lizards during the spring breeding season; at other times of the year, they are intolerant and aggressive with each other. To avoid contact with adults, juveniles usually select different micro-habitats. This behaviour is likely driven by the possibility that green lizard populations are regulated by mechanisms dependent on population density, where competition for living space leads to high predation on the juveniles by adults and often fatal attacks on females by large males. The outcome of this is that adult numbers drop, enabling juveniles to prosper and the population to eventually recover. Recent research by herpetologists in the south of France has also indicated similar density-dependent effects in the related Lacertid lizard (Zootoca vivipara). However, populations can be impacted by other factors including, among other things, annual changes in climate or high levels of predation.

Predators and Survival Strategies

Predators of both wall and green lizards include birds and small mammals, and the western whip snake Hierophis viridiflavus is a major predator. Laboratory studies have shown that lacertid lizards are able to detect the presence of this lizard-eating snake which is supported by observations of wall lizards in the Vendée. Here, they have been seen to leave hedgerows and move onto more open ground when a foraging whip snake is present. This escape tactic exploits the reluctance of whip snakes to enter open ground due to the risk from predatory birds, especially buzzards. Many individual lizards show examples of previous tail loss, which suggests high predation attempts but this can also occur during aggressive interactions between individual lizards.

Climate Change and the Lizard Expansion

The high adaptability of lizards along with climate warming has enabled green and wall lizards to colonise areas far outside their natural ranges. For example, wall lizards have colonised parts of the USA and Canada and continue to expand their range there, including by means of expansion along railway lines enabling the colonising of new areas and towns. Both wall and green lizards are now present and widespread in the UK and other areas of northern Europe where they have adapted to new and often colder environments.

It is believed many of these new UK populations originated from individuals which escaped from pet shops or the houses of pet keepers or which have been deliberately released. Recent research at Oxford University showed that female wall lizards have adapted to the cooler climate in England by evolving faster embryo development at lower temperatures. This enables the hatchlings to emerge earlier in the season than would be normal thus enhancing their rate of survival.

Windows Into Evolution

Over 7,000 species of lizards are found worldwide, making them incredibly diverse in form, size and lifestyle. Scientists often refer to them as the ‘windows of evolution’ due to the insights they provide into how species adapt to different environments. Their reproductive strategies alone are remarkably varied. While most lizards reproduce through normal means, some species use environmental sex determination, where the temperature during egg development determines whether the hatchling will be male or female. Other females can store sperm for many years, though fertility declines over time. Perhaps most remarkable are the 39 species that reproduce through parthenogenesis (virgin birth), where all-female populations produce what are effectively clones of themselves. Some lacertid lizards fall into this category, though our local green and wall lizard populations reproduce in the traditional way.

So, as the warmer days arrive and you start to see lizards scuttle away as you approach, take a moment to reflect upon how privileged we are to live so close to such fascinating creatures. Next time you spot one basking on your garden wall, you’ll know a little more about the remarkable life it leads.