Ramarro Occidentale (Lacerta Bilineata): Descrizione Della Specie
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FAMIGLIA:
Il ramarro occidentale è un sauro verde della famiglia dei Lacertidi, originaria dell'Europa, dell'Africa e dell'Asia. Il gruppo include il genere Lacerta, che contiene alcune delle specie di lucertole più comunemente viste in Europa. È una famiglia diversificata con almeno 300 specie in 39 generi.
È interessante notare che gli articoli die Wikipedia nelle 4 diverse lingue che ho consultato per questa pagina differiscono per alcuni piccoli dettagli e anche per la quantità di informazioni che offrono (l'articolo più informativo su questa particolare lucertola è quello di Wiki tedesco). Un esempio di queste differenze è come gli articoli non sembrano del tutto concordare sulla taglia/lunghezza dell'animale: Wiki inglese, spagnolo e tedesco affermano che i ramarri raggiungono una lunghezza fino a 40 cm, mentre Wiki francese parla solo di una media dimensione di 30 cm, e Wiki italiano dice che la specie raggiunge i 45 cm.
A giudicare dalle mie stesse osservazioni, sono decisamente d'accordo con Wiki italiano; ho stimato la lunghezza dei lucertoloni maschi più grandi che ho incontrato nella regione del Malcantone in Ticino (Svizzera) a più di 40 cm. Sembrerebbe logico però che ci siano differenze regionali nelle dimensioni della specie. Ad ogni modo, nei casi in cui le informazioni variano leggermente tra i diversi articoli, ho semplicemente optato per un compromesso (il che significa che in questo caso ho scritto che la specie Lacerta bilineata raggiunge tipicamente una lunghezza compresa tra 30-45 cm). Per le pagine originali di Wikipedia, basta cliccare qui: Español, Italiano; Français; English; Deutsch.
ETIMOLOGIA
Le parole latine "Lacerta" e "bilineata" significano "lucertola" e "con due linee". Il nome specifico è un riferimento alle linee pallide presenti sui fianchi dei giovani individui.
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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 (
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.
As reptiles, the lizards are ectotherms, meaning their body temperature depends on that of their environment. This, by the way, is also why the best time to observe Lacerta bilineata is during the morning hours in spring when the air is still relatively cool, because the animals need to raise their body temperature before they can get into action mode. That's when you'll be able to spot them in places that are exposed to the morning sun, taking extensive sunbaths (which they often also do in the evening). Once they're warm enough to get more active, the lizards go hunting in the grass and in the bushes, where their green color makes them virtually disappear.
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 grassland, arable land, and pastureland (most of which can thankfully be found in and around my garden). It is threatened by habitat loss.
