An animal that falls into this category is active during the day. Animals that fit this description typically use sight for hunting prey. Others, like turtles, are active during the day as they need the sun’s rays to aid in the production of vitamin D, which is needed to help process calcium and prevent metabolic bone disease. Hummingbirds rely on the sun as most of the nectar they gather comes from flowers that are open during the day. Cows, dogs, elephants, butterflies, and squirrels, for example, are diurnal.
