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Writer's pictureLacerta Bilineata

Green Lizards Changing Color: A Case Study


Western green lizard (Lacerta bilineata), male with blue head and throat and bright green body during mating season
Male western green lizard

With its blue head and emerald green body, the green lizard is undoubtedly the most colorful reptile species in Central Europe. However, this is only true in spring and early summer during mating season.


A western green lizard (Lacerta bilineata) couple, the male on the left (blue-headed), the female on the right (turquoise-headed), during mating season (June 2024)
A western green lizard couple, the male on the left (blue-headed), the female on the right (turquoise-headed), during mating season

Green lizards of the species Lacerta bilineata (the "Western" green lizard) and Lacerta viridis (the "European" green lizard) only show themselves in all their colorful splendor from around May to June.


For the rest of the year, the lizards are usually much less intensely colored and consequently much harder to spot, as their green color serves as excellent camouflage in the grass and bushes.


Male western green lizard (Lacerta bilineata) with less intense green colors that blend well with the surrounding leaves (August 2021)
Male western green lizard (Lacerta bilineata) with less intense green colors that blend well with the surrounding leaves (August 2021)
Female western green lizard (Lacerta bilineata) perfectly camouflaged with "normal" coloration outside mating season (August 2021)
Female western green lizard, perfectly camouflaged with "normal" coloration outside mating season

The change to the more colorful "wedding suit" takes place from around April to May, with the first molt after hibernation. The difference from the "normal" coloring is particularly pronounced in the males, whose face and throat often appear bright blue or turquoise during mating season.


Male western green lizard (Lacerta bilineata) during molt; the new skin is bright blue and turquoise on the face, while the old skin is almost gray in comparison (June 2024)
Male western green lizard during molt

The females also change color, although a little less noticeably. However, there are great differences in the coloring and color changes of green lizards, both regionally and within the same population.  In the case of females in particular, it is difficult to determine in the wild which patterns and colors are due to individual or regional variations rather than due to the season.


Female western green lizard (Lacerta bilineata) with a rather unusual color pattern (June 2024)
Female western green lizard with a rather unusual color pattern

To know exactly what the change in color looks like from autumn to mating season in spring, one would have to observe the same individual during different periods of the year, and that's precisely what I did. Last fall I photographed a male and a female western green lizard, and I was lucky enough to be able to track them down again in June of this year (green lizards are territorial and can often be found in the exact same places; in addition, each animal has an individual scale pattern on its face, which enables clear identification).


These two individuals offer a perfect case study which allows me to demonstrate how exactly their color changes. So here's the comparison between September 2023 and June 2024:


Male western green lizard in autumn 2023 with inconspicuous coloration (Maggia Valley, Ticino, Switzerland, September 2023)
Male western green lizard in autumn 2023 with inconspicuous coloration (Maggia Valley, Ticino, Switzerland, September 2023)
The same male western green lizard as in the picture above, but photographed here in early summer during mating season (Maggia Valley TI/CH, June 2024)
The same male western green lizard as in the picture above, but photographed here in early summer during mating season (Maggia Valley TI/CH, June 2024)
Female green lizard of the species Lacerta bilineata, outside mating season in fall (Maggia Valley TI/CH, September 2023)
Female green lizard of the species Lacerta bilineata, outside mating season in fall (Maggia Valley TI/CH, September 2023)
Female western green lizard, the same individual as in the photo above, but photographed here during mating season in June (Maggia Valley, TI/CH, June 2024)
Female western green lizard, the same individual as in the photo above, but photographed here during mating season in June (Maggia Valley, TI/CH, June 2024)
Western green lizard (Lacerta bilineata) in the fall (September 2023)
The same male in autumn...
Western green lizard (Lacerta bilineata) in spring (June 2024))
...and in spring
female western green lizard (Lacerta bilineata) in autumn (September 2023)
The same female in autumn...
female western green lizard (Lacerta bilineata) during mating season in spring (June 2024)
...and in spring

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