Why does a fly rub its front legs?

Answer

A fly is very different from me or you or your sister: they smell and taste with their legs. That may sound a bit strange, but it is true! They have special organs on the hairs of their legs. This allows them to absorb smells and tastes. They can taste things just by walking over them!

Flies keep the hairs on their legs clean by rubbing them together. They do this almost continuously when they are not flying. In this way they ensure that they can smell and taste everything well and that the hairs remain healthy. You can compare it to brushing your teeth!