noun, noun which may take the genitive case particle 'no'
nocturnality; nocturnal
Describes animals or habits that are active at night. Often used as a noun or with の to modify another noun.
Owls are nocturnal birds.
猫は本来夜行性だと言われている。
Cats are said to be naturally nocturnal.
Compound of 夜行 (yakō, 'night travel' or 'nocturnal movement') + 性 (-sei, 'nature' or 'property'). The term is a straightforward Sino-Japanese word.