Viviparous lizard

This small lizard lives in many lands. It can live in very cold places. Some lizards lay eggs. But this lizard can give birth to live babies.

This lizard eats only bugs. It hunts flies and spiders for food.

In the winter, it gets very cold. The lizard can freeze in the cold. It stays frozen for two months. Then, it thaws out when it gets warm.

It likes to sit in the sun to stay warm. This lizard is a very tough animal.

The viviparous lizard is a small reptile.

It has a very large home. It lives in many lands across Eurasia. This lizard lives in very cold areas. Some lizards lay eggs to have babies. This lizard is viviparous. This means it can give birth to live young.

It can also lay eggs sometimes.

These lizards eat only insects. They hunt flies, spiders, and mealworms. This diet is called being insectivorous. They are active hunters. In the winter, they must stay safe from the cold. They often hibernate from October to March. Sometimes, they freeze in the cold. They may stay frozen for two months. Then, they thaw out when it gets warm. They like to bask in the sun to stay warm. This is called thermoregulation.

Males and females look different. Males often have larger heads. They also have bright colors on their bellies. Females often have dark stripes on their backs. Large males are often more successful at mating.

The viviparous lizard is a very special reptile.

It has the largest range of any land lizard in the world. This lizard lives in many places across Eurasia. It can even live in subarctic regions where it is very cold. The name "viviparous" describes a special way it has babies. It means the lizard can give birth to live young.

Sometimes these lizards will lay eggs normally instead.

To stay warm, these lizards use a way of life called thermoregulation. This means they actively control their body temperature. They do this by basking in the sun for a long time. In very cold weather, they hibernate from October to March. Some lizards even enter a "supercooled" state to survive the winter. In the coldest seasons, they can actually freeze solid. They may stay frozen for two months until they thaw out.

They often live near groundwater that keeps the soil warm.

Scientists have studied these lizards for a long time. In 2007, researchers named Arnold, Arribas, and Carranza changed how we group them. They split the old group, Lacerta, into nine different groups. This lizard used to be called Lacerta vivipara. Researchers like Yann Surget-Groba have also studied how they have babies. They looked at how laying eggs changed into live birth.

This helps us understand how living things change over time.

These lizards are exclusively insectivorous, which means they only eat insects.

Their diet includes flies, spiders, mealworms, and moth larvae. They are active predators that hunt their food. Males and females can look quite different from each other. This is called sexual dimorphism. Males often have larger heads and brighter colors on their bellies. Females usually have darker stripes on their sides and backs.

Larger males are often more successful at mating.

Understanding this lizard helps us see how life survives anywhere. They show us how animals handle very harsh weather. Even when it is freezing, they find a way to stay alive. Their ability to live in such wide areas is truly amazing. They connect many different lands from France all the way to Russia. You can find them in places like the British Isles and Japan. They are a great example of how nature works in many climates.

The viviparous lizard, also known as the common lizard (Zootoca vivipara), is a remarkable Eurasian reptile.

It holds the record for the largest distribution of any terrestrial lizard species in the world. This lizard can survive in much more varied climates than most other reptiles. It lives in environments ranging from the British Isles to Japan. It even thrives in subarctic regions. The species is named for its ability to be viviparous. This means it can give birth to live young.

However, some populations are oviparous, meaning they lay eggs instead.

To survive in cold climates, the lizard uses a process called thermoregulation. This is the active control of body temperature to maintain thermal homeostasis. Most animals in extreme cold use thermoconformity, where they simply adapt to the temperature. The viviparous lizard instead uses behaviors like basking in the sun to stay warm. In the harshest winters, it uses a "supercooled" state. This allows the lizard to survive in temperatures as low as -10°C. If temperatures drop further, the lizard can actually freeze solid. It may remain frozen for two months until it thaws out.

It often finds warmth in microhabitats near unfrozen groundwater.

There are distinct differences between male and female lizards, known as sexual dimorphism.

Males often have larger heads and more colorful undersides. Their bellies may show bright shades of yellow, orange, green, or blue. Males also typically have spots along their backs. Females usually have darker stripes on their sides and backs. Females also exhibit colour polymorphism more often than males. Their ventral coloration can range from pale yellow to bright orange. Researchers like Vercken et al. found this color variation is caused by social cues. This relates to patterns of sex allocation and reproduction.

Reproduction in this species is complex and involves different biological strategies. The ability to switch between laying eggs and live birth is a major focus of study. Some scientists believe viviparity evolved from oviparity only once. However, researcher Yann Surget-Groba suggests it may have evolved multiple times across different clades. He also suggests that reverting to egg-laying is not as rare as previously thought. In the Italian Alps, some populations are so different they might be separate species. These populations are reproductively isolated from one another. If they do hybridize in a lab, the embryos often show malformations.

Historically, the classification of this lizard has changed due to new research. It was once part of the genus Lacerta. In 2007, researchers Arnold, Arribas, and Carranza split Lacerta into nine different genera. This placed the common lizard into its own genus, Zootoca. This change helped scientists better understand the specific evolutionary path of the species. Understanding these taxonomic shifts helps us track how different reptile groups branched out over millions of years.

As an exclusively insectivorous predator, the lizard plays a specific role in its ecosystem.

It hunts flies, spiders, and various other insects. Its diet includes moth larvae, mealworms, and hemipterans like cicadas. Interestingly, the lizard's diet affects its health regarding parasites. Studies show that more carnivorous individuals have less diverse populations of parasitic helminths. These helminths are small parasitic worms. Larger lizards tend to carry a greater number of these parasites.

The lizard must also avoid many predators, including birds, snakes, and foxes.

The life of a viviparous lizard is defined by its incredible hardiness. Most individuals live for about 5 to 6 years. They reach sexual maturity during their second year of life. Male success in the wild is often tied to physical traits. Larger heads are a result of sexual selection. Males with larger heads are more successful in mating and male-male aggressive encounters. They also tend to reproduce more frequently during a single season. This combination of physical strength and environmental adaptation makes them a highly successful reptile.