We have ways of knowing about the world outside of our bodies. The way we do this is to use our senses. They are sight, hearing, taste, smell and touch.

Living things have senses balanced for their lifestyle. So, for example, a dog has a much more developed sense of smell than us because it uses smell to track its food. Animals that eat by night either have much better eyesight, like owls, a kind of night vision, or they use hearing (also owls). Cats have much better night vision than us, too.

When animals live permanently in the dark, such as moles, they have almost no eyesight and rely on sound, smell, and touch. Many animals, including moles, have whiskers to help them sense their world very close up by touch.

We can switch which sense is important to us a little, depending on our environment. If it is night, we tend to rely more on our ears. The trouble is that we are not really used to using our ears this way, and so we cannot always figure out what we hear, and we get anxious and sometimes frightened. That is why the world at night can be spooky, and why many horror stories are set in darkness.