Nocturnal animals sleep by day and hunt by night.

夜间活动的动物白天睡觉晚上猎食。

《牛津词典》

The nocturnal animals hide in underwater caves by day, then venture out at night, feeding on small fish, squid, and octopus.

这种夜行性动物白天时隐藏在水底洞穴里，晚上才出来冒险，它们以小鱼、乌贼和章鱼为食。

youdao

Many animals hunt by night.

许多动物在夜间猎食。

youdao

Later,a stagecoach could make the trip in thirteen to fourteen days by moving day and night and changing animals often.

VOA: special.2009.03.30

Quite by chance, Berryman's cartoon was noticed by a Russian Jewish immigrant to America named Morris Michtom, who by day sold candy in his store in Brooklyn, while by night making stuffed animals with his wife Rose.

BBC: A Point of View: The grown-ups with teddy bears