Pandas were thought to fall into the crepuscular category, those who are active twice a day, at dawn and dusk; however, Jindong Zhang found that pandas may belong to a category all of their own, with activity peaks in the morning, afternoon and midnight. Due to their sheer size, they can be active at any time of the day. Activity is highest in June and decreases in late summer to fall with an increase from November through the following March. Activity is also directly related to the amount of sunlight during colder days.