nocturnal
adjective formal uk/nɒkˈtɜː.nəl/ us/nɑːkˈtɝː.nəl/
夜间发生的;夜间活动的;夜间的
happening in or active during the night, or relating to the night
nocturnal wanderings 夜游
nocturnal light 夜光
Most bats are nocturnal. 大部分蝙蝠在夜间活动。
Compare: diurnal