Psalm 104:20 (ESV)

20 You make darkness, and it is night, when all the beasts of the forest creep about.

Again, it is clear that the Creator controls everything. He determines the rhythm of day and night, of light versus darkness. Many, humans for example, must stop their daily tasks when darkness comes over the earth. However, the night is especially the time to become active for many animals in the woods. They come alive and start to hunt for the food they need (to survive).