We live in a world flooded with light 24 hours a day. Before our recent harnessing of electricity, light was a reliable indicator of seasonal variability in resources and many species evolved to take advantage of this signal. Robertet al. show that artificial light can alter these species physiological responses and desynchronize their seasonal reproduction. Specifically, they found that nocturnal tammar wallabies that lived near a continuously lighted military base secreted less melatonin at night and that this delayed reproduction by nearly a month, as compared to animals living without artificial light nearby. Animals living near the base attempted to avoid lighted areas, but these results suggest that light pollution may have unavoidable physiological effects.
