Research overview: circadian disruption from artificial light in urban wildlife

Artificial light at night can disrupt the internal circadian clocks that govern activity, hormone cycles and reproduction in animals, with potential consequences for nocturnal carnivores. This overview synthesises chronobiology and ecology research on how light exposure alters circadian rhythms and melatonin signalling in wildlife, and the implications for felids whose activity, breeding and physiology are tuned to natural light-dark cycles. It examines how city lighting could desynchronise these rhythms even where animals remain behaviourally nocturnal. The synthesis frames circadian disruption as a physiological dimension of light pollution that may affect urban felids in ways not captured by behavioural observation alone.