What does the term 'nocturnal' refer to?

The term 'nocturnal' specifically refers to animals that are active during the night. These animals have adapted to being awake and performing their activities such as hunting, foraging, or mating in the dark, which can provide advantages such as avoiding predators or conserving water in hot environments. Nocturnal species often possess specialized adaptations, like enhanced night vision or keen hearing, to help them navigate and thrive in low-light conditions.

This definition distinguishes nocturnal animals from those that are diurnal, which are active during the day. For example, animals that primarily eat plants may not necessarily have a specific activity pattern tied to night or day; many herbivores can be either diurnal or nocturnal depending on their environment and survival strategies. Most mammals, such as humans and many birds, are diurnal, which again contrasts with nocturnal behavior. Hibernation refers to a state of inactivity during certain seasons, typically winter, to survive adverse climate conditions, which does not align with the concept of being nocturnal either.