Although they are occasionally seen during the daylight hours, deer are primarily nocturnal creatures. They tend to appear mainly at dusk or at dawn to browse for food.
Nocturnal animals, such as deer, are able to see at night. Their eyes contain more light-detecting cells than the eyes of diurnal creatures, and this trait enhances their vision in dark or low-light situations. Experts believe that deer are also able to see in the ultraviolet light range, which is prevalent in the early morning and late afternoon hours. This is another reason that deer tend to be active during those periods.