Lizards living in cities have developed features that their cousins living in the forests do not have. Animals living in the “concrete jungle” of Puerto Rico had longer limbs and larger fingertips than forest reptiles, according to a study by scientists in New York. Interestingly, populations living in different cities independently developed the same adaptations.
Urban growth has affected many animal species around the world, replacing natural ecosystems with concreted, hot areas. However, many organisms manage to survive in a new environment and even develop. Researchers studying evolutionary changes in urban species have found that some populations adapt their metabolism to a new diet or show an increased tolerance to heat. The study, published in the journal Proceedings of the National Academy of Sciences, gives us a deeper insight into the mechanisms of “urban evolution” in lizards.
The difference is in the genes
Researchers from New York University looked at 96 representatives of the species Anoles cristatellus. They are relatives of iguanas living in Puerto Rico and the Virgin Islands in the Caribbean Sea. The researchers analyzed individuals living in three urban centers in Puerto Rico – San Juan, Arecibo and Mayaguez – and compared them with lizards inhabiting nearby forests.
The study authors found that compared to their woodland cousins, urban lizards have much longer limbs and larger fingertips with specialized scales on the fingers. These features developed independently in each population – animals from different cities differed from each other in terms of genetics.
“The differences we see in urban lizards seem to be reflected at the genome level,” explained Kristin Winchell, author of the study. ‘If urban populations change physically and genetically at the same time, we can even predict from their genes how they will adapt to living in an urban environment.’
Anolis cristatellus lizardAdobe Stock
Faster and more stable
Winchell’s earlier research showed that individuals A. cristatellus those living in urban areas have larger fingertips because these allow them to cling tightly to smooth surfaces such as walls and glass. Their long limbs, on the other hand, help them glide quickly through open areas.
Scientists explain that understanding how animals adapt to urban environments can help us create conservation programs for the most vulnerable species. This knowledge will also be useful for urban planners, who will be able to use it to transform cities into more animal-friendly areas.
“Urbanization is currently taking place on about two-thirds of the Earth’s surface and is expected to continue to increase,” explains Winchell. ‘Cities provide us with natural laboratories for studying adaptive change, as we can compare urban populations with their non-urban counterparts to see how they respond to similar stressors and pressures over short periods of time,’ he adds.
Main photo source: Adobe Stock