Common lizard

Latin name

Zootoca vivipara

Class

Reptiles

Group

Snakes & Lizards

Size: Adult lizards grow to a body length (i.e., from nose tip to vent) of 6-7 cm (ca. 2.7 in.), with a tail up to twice their body length, resulting in a lizard that's typically 13-20 cm (5-8 in.) in total length. Adults of both sexes weigh 2 to 5 g (0.07-0.2 oz.), while gravid females may weigh significantly more – typically up to 8 g (0.3 oz.), although a female caught under a dry-docked sailing boat on Germany's Baltic Sea coast near Vitte during June 2011 weighed 10 g (0.35 oz.).

Colour/Appearance: These are short-legged lizards, presenting with a small, rounded head and a thick neck and tail, which tapers to a point. It is common to find adults with much shorter conical tails that have grown back from autotomy. Autotomy is the process of shedding an appendage -- in this case, the lower two-thirds of the tail -- when caught by a predator. The shed appendage typically continues to move, acting as a distraction to the predator while the lizard makes its escape. Shed tails are never regrown to their original length or with original colour/pattern, but this does not appear an impediment to the owner. Skin is periodically shed (sloughed) which happens in pieces, rather than all at once as in snakes.

Typically, animals are a mottled olive, dark brown, or dark grey with light and dark spots (called ocelli) and pale parallel lines running down the back from the base of the head to the hips, where the lines become broken spots. There's considerable variation in colouring, patterning, and scaling, even with populations, and there are reports of pattern-less phenotypes that, as the name suggests, lack any of the linear markings. Underside varies from white to orangey-red, with an off-white or bluish throat. Hypomelanism (i.e., presenting with a "washed out" or pastel colouration) has been reported from The Alps and hypermelanism (i.e., jet-black individuals) occurs occasionally throughout the range. Males can appear quite strikingly green with orange bellies during the breeding season, and a bright blue (cyanistic) individual was photographed in a central Bedfordshire garden during June 2020. Juveniles are much darker than adults; jet black at birth, lightening to a blackish-bronze by their first autumn.

Distribution: Appears to be the most widespread terrestrial reptile in the world, ranging from the Cantabrian mountains and Ireland in the west, throughout Eurasia to Russia and Japan in the east. They are found from the Po Valley in Italy and south Bulgaria in the south, north to the Barents Sea. In the UK, it's found throughout England, Scotland, Wales and Ireland, although is absent from most Scottish islands and the Channel Islands.

Habitat: This species is found in a wide range of habits, including heathland, moorland, woodland, dunes, coastal cliffs, chalk downland, and grassland, provided cover and invertebrate prey are available. They may also be found along railway and road embankments, even in gardens, particularly those that are south-facing. Common lizards appear tolerant of a range of conditions and can even be found in wet environments such as bogs, marshland, and rice fields, but they prefer sites with low levels of disturbance and appear rare in intensively farmed landscapes.

Longevity: Typical lifespan in the wild considered 5 to 6 years, although they have the potential to live longer; some marked males have reached 8 years and females 12 years old. Lifespan in captivity does not appear to exceed that in the wild.

Sexing: Males typically have a broader head and neck than females and a hemipenal bulge near the root of the tail. Females are generally fatter than males, especially when pregnant. Sometimes the sexes vary in colouration and/or patterning, but this cannot be relied upon in isolation. Ocelli tend to be better developed in males, while females often have darker flanks and a paler back with a continuous dark vertebral stripe. Males may present with dark spots on the belly, which are uncommon in females. In the days having given birth, females often present with flaccid skin along the flanks. Females may also present with U-shaped scars caused by courting males.

Activity: Common lizards are mostly ground-dwelling, although may climb walls and into dense vegetation to bask. Activity is primarily diurnal (daytime), but very warmth may promote some nocturnal activity as it appears to in other reptiles (e.g., adders), and periods are divided between hunting and basking. Males are more active than females during the spring breeding season, chasing and sometimes fighting one another. In Britain, hibernation is typically from October to March. Hibernation is normally undertaken in burrows, among dense vegetation, in deep leaf litter, or under logs/rocks to shield the animals from frost. Studies by Daniil Berman and colleagues demonstrated this species could survive in a frozen state for 2 months at -3C (27F) before thawing out, at which point they immediately restored their skin pigmentation, and were able to tolerate soil temperatures of -10C (14F) provided the air is dry. Unlike snakes, lizards tend to hibernate solitarily. The same study reported lizards entering hibernation when temperatures dropped to 5C (41F). Males emerge from hibernation as much as 3 weeks before females, presumably to start sperm production in preparation as they're infertile for about 2 weeks following emergence.

Territory/Home Range: As with most species, this seems dependent on habitat quality, being smaller in rich areas. Data from France, published in 1990, found both sexes ranged over 500 to 600 sq-m (0.1 acre), although one range of just under 1,700 sq-m (0.4 acres) was recorded.

Diet: This species feeds primarily on small invertebrates, all of which are actively hunted. Species taken include a variety of small insects, including cicadas, butterfly and moth caterpillars, and flies, as well as spiders, small snails, and worms. Females appear to eat more than males (controlling for body size), and food consumption is linked with ambient temperature; more food is taken in warmer weather. In the wild, common lizards appear to stop feeding when their core temperature drops below 27C (81F), although they will feed with lower body temperatures in captivity.

Reproduction: Males may chase and fight one another for mating rights, and courtship involves the male biting ("capture") the female, often resulting in the pair rolling together, and some data suggest males with larger heads have higher mating success. Courtship may last anywhere from 5 to 30 minutes, during which several copulation attempts are made. A female's mating window appears to start at copulation and remain open (i.e., the female is receptive) for up to 20 days. Mating takes place about 2 weeks after emergence from hibernation, from early March to early May, resulting in litters born predominantly during July and August following a gestation of 6 to 13 weeks, depending on daytime temperature. As their common name alludes to, this species gives birth to live young in parts of its range. In Britain, litters of up to 12 young (typically 5-7) are born in transparent membranous egg-like capsules from which they soon break free. Further south in their range (south-west France and Spain, for example) females lay clutches of up to 13 eggs, sometimes communally, which develop and hatch after about 5 weeks. Presumably, warmer temperatures in the south of their range are more conducive to egg development. Young are 1.5 to 2 cm (0.8 in.), 4 cm (1.6 in.) with tail, at birth and may be found basking with littermates. Both sexes can be sexually mature in their second year, but more typically most won't breed until 3 years old. In the central Pyrenees, Juan Roig and colleagues found larger males appear to release more sperm per copulation than smaller ones, perhaps resulting in higher probability of fatherhood. Both sexes will mate with multiple partners during the breeding season. A second or third clutch/litter may be produced if conditions allow and mate availability is high.

Behaviour and Sociality: While littermates may be found basking together during their first summer, this is a primarily solitary species. Communication appears to be mediated primarily by scent, hormones secreted from glands on their thighs ("femoral pores") and detected through tongue-flicking. Lizards manage their body temperature by means of behavioural thermoregulation -- i.e., they readily bask (close to cover) to warm up and move into the shade to cool down. They may sit with their body flattened to the ground ("pancaking") in sunny spots on cooler days to expedite warming. Females bask extensively while pregnant. Intriguingly, one study on lizards from Mont Lozère in southern France, published in 2008, found females with yellow bellies were highly aggressive towards other females, while those with orange undersides were much more passive.

Predators: Lizards are vulnerable to birds of prey (especially kestrels and great grey shrikes), corvids (especially magpies, jays and carrion crows), blackbirds, and larger reptiles (especially adders and smooth snakes). A study in Belgium, published in 2020, found lizards responded to chemical cues in shed adder skins, even after washing. Pheasants appear to be significant predators of some populations. Among the mammals, stoats, weasels, hedgehogs, and domestic cats probably represent their main predators, while foxes will take adults occasionally and shrews may take juveniles. Some individuals may present with a high tick burden.

Threats: Some site recorders (e.g., in Dorset, UK) have commented on declines in common lizards associated with increasing wall lizard abundance, although data are limited. Climate change, particularly changes in rainfall causing habitat shifts and reductions in invertebrate prey, and habitat loss are also impacting some populations in the UK and Europe. In The Netherlands, for examples, work by Raymond Creemers has identified significant declines since the mid-1990s, with some populations having disappeared completely. Populations in Scotland appear to be doing better than those in England, where there's increasing concern over declining abundance.

Common lizard in detail

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Bibliography

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