they take their ques from the photoperiods (amount of daylight) after the first day of summer the days begin to shorten as they do animals pick up on this and prepare for winter...at least temperate animals. they think it's winter but it's still warm so they don't hibernate but...a part of them still goes into that mode...some completely stop eating, others slow down. they are kinda torn...nothing harmful. if you get it away from any exposure to daylight and put artificial lights on them with a timer to simulate peak summer hours...they tend to stay active and have a normal appetite. it's all natural...grey squirrels begin hiding nuts, bears put on the fat, deer get ready for the rut and many birds start looking southward.