The Viviparous Lizard (Zootoca vivipara), or common lizard, is a Eurasian species known for being viviparous, giving birth to live young. It is the northernmost non-marine reptile and was reclassified from the genus Lacerta in 2007.
Zootoca vivipara has a small size, with an average length of 150-200 mm, and exhibits various colors, including brown, red, grey, green, or black. Females often show color polymorphism in their ventral coloration, which ranges from pale yellow to bright orange. Studies suggest this polymorphism may relate to social cues during reproduction, while males typically have brighter colors and larger heads, giving them an advantage in mating.
These lizards are exclusively carnivorous, feeding on flies, spiders, and insects, and they thermoregulate by basking and hibernating from October to March. Their habitats include heathland, moorland, woodland, and grassland. Zootoca vivipara is widely distributed across northern Eurasia, found north of the Alps and Carpathians in Europe and throughout parts of Asia, making it the lizard species with the largest range globally.
The viviparous lizard, Z. vivipara, is exclusively carnivorous, preying on flies, spiders, and various insects, including hemipterans and mealworms. Females tend to consume more food than males, and their feeding rates increase with sunlight.
This lizard is named for its ability to give birth to live young, although it can also lay eggs. There is debate about the evolution of viviparity from oviparity; some scientists believe it has occurred multiple times in different populations, and reversion to egg-laying is more common than previously thought.
Z. vivipara’s viviparous populations range from France to Russia, while oviparous populations exist only in northern Spain and southwestern France. Research suggests that these distinct populations may be considered separate species due to reproductive isolation, with hybridization causing embryonic malformations, yet generating offspring that have longer gestation periods.
