noun, plural: nocturnalities
(1) The condition of being active or occurring during the night
(2) The active behavior of an animal or plant during the night (and then inactive during the day)
Nocturnality refers to the condition of being active or occurring during the night and not during day time. It may particularly pertain to the behavior of an animal or a plant that is active during the night and not during the day. It is in contrast to diurnality wherein it is associated with a behavior that is active during the day and not at night. Nevertheless, similar to diurnality, nocturnality in regards to behavior may be influenced by environmental factors, e.g. temperature, food hunting, and predation risk. An animal or a plant that is active at night is described as nocturnal (whereas those that are active during the day are described as ”diurnal). For instance, animals that actively hunt and plants that bloom at night are described as nocturnal. Nocturnal animals often have a highly developed sense for smell and hearing. They also have eyesight adapted for low light levels. Tarsiers and nocturnal owls have eyes that are large relative to diurnal animals. Their large eyes enable them to have improved visual sensitivity in low-light conditions.
Word origin: Middle French nocturnal, Latin nocturnus (“nocturnal, nightly”), Latin nox (“night”)