Grand jury is so named because traditionally it has greater number of jurors than trial jury, called a petit jury (from the French word petit meaning small).
Although mice tend to come out in the night when most of the occupants of the house are asleep or immobile. This allows them to stealthily infiltrate any of your food bags, crumbs etc. During the day time, mice will normally not come out, but if opportunities exist then they surely can.
Nocturnal animals are awake and active at night and then sleep during the day. Some nocturnal animals can be seen during the day, but most of them spend their whole day resting. Examples of nocturnal animals include bats, skunks, aardvarks, and owls. Nocturnal animals sleep during the day for various reasons. Most nocturnal animals sleep during the day and are active at night in order to avoid predators that are active during the day. For example, sea turtles go to their breeding sites in order to keep themselves safe and protect their offspring. Most nocturnal animals live in the desert.