Data from: Artificial light at night desynchronises strictly seasonal reproduction in a wild mammal

Change in day length is an important cue for reproductive activation in
seasonally breeding animals to ensure that the timing of greatest maternal
investment (e.g. lactation in mammals) coincides with favourable
environmental conditions (e.g. peak productivity). However, artificial
light at night has the potential to interfere with the perception of such
natural cues. Following a 5-year study on two populations of wild
marsupial mammals exposed to different night-time levels of anthropogenic
light, we show that light pollution in urban environments masks seasonal
changes in ambient light cues, suppressing melatonin levels and delaying
births in the tammar wallaby. These results highlight a previously
unappreciated relationship linking artificial light at night with induced
changes in mammalian reproductive physiology, and the potential for
larger-scale impacts at the population level.