Light pollution, or artificial light at night (ALAN), is a rapidly spreading form of environmental degradation that currently covers about 50% of the United States and 90% of Europe. It can have wide-ranging impacts to nocturnal wildlife by causing changes in foraging behavior, space use, predator-prey interactions, communication and reproduction. New research published this week in the journal Ecology and Evolution demonstrates how disruptive ALAN can be to some bat species of the northeastern U.S.