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.
up vote 3 down vote. It's some kind of bug - not a vertebrate. If you're not seeing it at all during the day, go out at night. One common bug that does this that you should be able to spot during the day is the cabbage looper - green caterpillars with two white stripes on each side.