The term "diurnal" refers to activities or behaviors that occur during the daytime. Many animals, including birds and squirrels, are considered diurnal because they are most active when the sun is up. This behavior is often linked to the availability of light, which helps these creatures find food and avoid predators. In contrast to diurnal animals, there are nocturnal species that thrive at night. Diurnal patterns can also apply to plants, which may open their flowers during the day to attract pollinators like bees. Understanding diurnal rhythms is important in fields such as ecology and chronobiology.