Bielefeld University study shows how urban life reshapes wall lizard behavior.

Streets, walls, concrete, cities may seem like a harsh environment. Yet some animals adapt remarkably well. The new study “City lizards are more social” in Biology Letters shows that common wall lizards (Podarcis muralis) behave far more socially in urban areas than in the countryside. The research team led by first author Avery Maune from Bielefeld University studied lizard populations in Croatia, with striking results.

“Our findings show that wall lizards in cities maintain many more contacts and develop stronger bonds than their counterparts in natural habitats,” says Maune, a doctoral researcher in the group of Professor Barbara Caspers at the Faculty of Biology. “That is remarkable because these lizards are usually highly territorial and tend to avoid one another.”

Urban structures foster closeness
To uncover the social patterns, the team used social network analysis, a method often applied in behavioral research to map relationships between individuals. The results were clear: in urban habitats, wall lizards built more connections, stayed in closer contact, and were observed in groups more frequently.

The scientists link this shift to the structure of city environments. Sealed surfaces, limited hiding places, and unevenly distributed resources such as food or sunny spots push the animals closer together. The result: greater tolerance toward neighbors, a behavior not observed in natural habitats.

Adapting to life among walls
For the researchers, these findings highlight more than just a behavioral quirk. “The ability to develop new social strategies could be crucial for species to persist in urban environments,” Maune emphasizes.

The study team includes, alongside Maune, Tobias Wittenbreder and Professor Barbara Caspers from Bielefeld University, Professor Dr Duje Lisičić from the University of Zagreb, Dr Ettore Camerlenghi from Collegium Hellveticum in Zürich and Dr. Isabel Damas-Moreira from Bielefeld University as senior author.

The work also draws on expertise from the Collaborative Research Center NC³ (Niche Choice, Niche Conformance, Niche Construction). This research consortium, coordinated at Bielefeld University with partner institutions, investigates how animals shape their ecological niches and adapt to changing environments.