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Lagarto Verde Occidental (Lacerta Bilineata): Descripción De La Especie

Westliche Smaragdeidechse (Lacerta bilineata), ausgewachsenes Männchen während der Paarung

I spend a lot of time observing western green lizards, but I'm by no means an expert on Lacerta bilineata. So because I want to provide anyone who comes to this site with accurate information on the species rather than just my own findings and speculations, what you'll read below is more or less directly copied from French, Italian, English and German

Interestingly, the Wiki articles in the different languages differ in some small details and also in the amount of information they offer (the most informative article about this particular lizard is the one in German for those who are interested). An example for some of the differing details would be how the articles don't quite seem to agree on the size/length of the animal: English and German Wiki  state that the lizards reach a length of up to 40 cm, while French Wiki only speaks of an average size of 30 cm, and Italian Wiki claims the species reaches up to 45 cm.

 

From my personal observations I definitely agree with Italian Wiki as I estimated the size of the largest males I encountered in the Malcantone region of Ticino (Switzerland) - which is where I took all the photos on this site - at more then 40 cm. It would appear logical though that there are regional differences in the size of the species. Anyway, in such cases where the  information slightly varies across the different articles, I went with a good old compromise (which means here you'll read that the species Lacerta bilineata typically reaches a size of between 30-45 cm).

 

For the original Wikipedia pages, just click on the links here: Italiano; Français; EnglishDeutsch.

ETYMOLOGY

The genus name Lacerta and the species name bilineata are Latin words respectively meaning “lizard” and “with two lines”, with reference to the pale lines present on the flanks of the young individuals.

Western Green Lizard | Lacerta Bilineata | Adult Male In Honeysuckle Bush | Spring 2021
Westliche Smaragdeidechse (Lacerta bilineata), Weibchen
Distribution of Lacerta bilineata and Lacerta viridis.jpg

The closest relative of the western green lizard is the European green lizard (Lacerta viridis; Wikipedia link: It; Fr; En; De) which is more common in south-eastern regions of Europe. The two species are not easily distinguished without genetic analysis and get often confused; in fact, they were only recognized as different species as recently as 1991. The map shows the distribution range for Lacerta bilineata (green) and Lacerta viridis (blue) and the small area (yellow) where a degree of hybridization between the two species occurs (link for the map: Wikipedia). 

Lacerta bilineata is native in Andorra, Croatia, France, Germany, Italy, Monaco, Serbia, Slowenia, Spain, and Switzerland. It was introduced in Guernsey and Jersey in the Channel Isles and the United States, and there are also introduced colonies on the south coast of the U.K, notably around Poole Bay in Dorset.

 

DESCRIPTION

Adult western green lizards reach a length of 30 to 45 centimeters including tail (there may be regional differences regarding the size of the species). The tail may reach up to twice the body length. The average weight is about 35 grams. Males are generally a bit bigger than females, with a slightly bulkier head and body.

 

With females of the species colors and color patterns can vary greatly and range from dark green and brown to shining emerald green, turquoise and blue and everything in between, even colors that are more typical for males.

Adult males tend to look more alike (though there are variations too), with their back usually a striking yellowish to emerald green interspersed with black dots, a yellow or yellow-green belly and blue face, all of which much more pronounced during mating season (the adult male lizards in the gallery below were all photographed during mating season in May, when their colors were particularly intense, except for the last 4 photos, which were taken in August and September).

As juveniles the lizards are mostly brown with a yellowish green chest and belly. Within a year, as adolescents and sub-adults, they develop white lines or dots on both flanks often in combination with black spots until their eventual color patterns start to shine through (as already mentioned above, those two white lines are also responsible for the species' Latin name "bilineata" which means "two-lined") .

REPRODUCTION, BEHAVIOR, DIET AND LIFE EXPECTANCY

 

Western green lizards attain sexual maturity at around two years. They are territorial animals; the males fight each other, especially during the mating period, when they are very aggressive towards rivals. The mating ritual is precise, and starts with a bite to the base of the female's tail. The females lay 6 to 25 eggs in a humid and warm site, such as in a decomposing log. The baby lizards hatch after 70 - 100 days depending on the surrounding temperatures and already have a size of 8 - 10 centimeters.

Mating western green lizards (Lacerta bilineata)

As reptiles, the lizards are ectotherms, meaning their body

 

Western green lizards are predators and very agile hunters. Like most lizards they're excellent climbers and often hunt in bushes and trees, depending on their habitat, but they can also jump pretty high as you can see in the first video clip below (the animal in the clip is an adult female who had seen an insect she desired). They feed on arthropods, mainly large insects, but basically anything they can overwhelm that fits into their mouth ranging from small lizards to baby mice is on their menu (the animal in the second clip is a juvenile foraging for food).  They themselves are prey to cats, foxes, martens, weasels, birds of prey and snakes (and other predators who hunt animals of comparable size).

It is assumed that western green lizards can have a life span of 10 - 15 years, although most individuals don't survive their first year.

 

During the coldest months of the year, western green lizards hibernate, usually from around mid-October; the exact time depends heavily on the temperatures. In ideal weather conditions, they emerge from their winter hiding places around the middle of March, usually the males first, followed by the females a few weeks later.

HABITAT

 

The Lacerta bilineata's natural habitats are woods, shrubland, open grasslandarable land, and pastureland (most of which can thankfully be found in and around my garden). It is threatened by habitat loss.

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