What do the Terms Crepuscular, Diurnal, and Nocturnal Mean?
Crepuscular, diurnal, and nocturnal are terms which are used to describe the period of the day during which an animal is active. Many animals develop distinctive behavioral patterns which are part of their overall adaptation to the environments that they live in. Periods of activity tend to be easy for biologists to observe, and they are commonly used as tools to assess whether or not animals are stressed, frustrated, or pressured into unusual behavior. Knowledge about when an animal is supposed to be active can also be used as an indicator to suggest that an animal might be sick; owls, for example, are usually seen at night, making an owl a cause for concern if it is seen at noon.
