Modern cities are evolution engines. Urban snails in the Netherlands and lizards in Los Angeles have developed lighter shells and larger scales to cope with the heat island effect, where temperatures can be several degrees above the surrounding area.
Artificial light makes an artificial dawn, shifting the time when birds sing, and has prompted urban bridge-dwelling spiders to develop an attraction to light, whereas ermine moths are losing theirs altogether. A mutation in the so-called “daredevil gene”, also found in downhill skiers and snowboarders, is making urban swans bolder and more tolerant of humans.
