Why Do Flies Rub Their Hands Together?

You likely make this motion when you’re looking down, appreciating your favorite meal just before you savor it. You’ve seen villains rub their hands together and narrow their eyes when planning something evil. You’ve definitely caught a house fly or two rubbing their “hands” together while resting uncomfortably close to your snacks. But why do flies rub their “hands” together?  

What Are Flies?

Flies is a broad term that encompasses several different types of insects. There are small flies like phorid flies, drain flies, fungus gnats, and fruit flies that mostly go unnoticed unless you happen to focus your eyes and catch them swirling about a drain, your plants, or your ripe fruit. Then, there are larger flies like stable flies, cluster flies, flesh flies, and the most common, the house fly. This is the annoying fly that gets way too close to your food and drinks, whether you’re outdoors or indoors. It’s probably why you have a fly swatter ready and waiting somewhere in your home.

How Do Flies Sense Flavor?

Flies are unique in that they can sense flavor not just via tiny receptors in their mouths but using their entire bodies. They can detect different flavors, some sweet and pleasant and some sour and foul. So while you get to savor food using your taste buds and can appreciate the aroma of your favorite dish before it even touches your lips, flies have a different experience altogether. They can taste the food before they eat it! Their legs and wings get a taste of whatever they touch to determine if it’s yummy and worth eating or if it’s gross and worth leaving.

Why Do Flies Rub Their Hands Together?

Since flies can taste food with their legs, they can’t let tiny particles of everything they touch stack up on their bodies. As a result, they constantly need a clean slate to determine if the next food item is worth snacking on. If you take a moment to observe a house fly, you’ll notice it takes its time thoroughly clean its “hands,” but that’s not all they do. They also wash their faces, including their large eyes.

They rub their little legs against different parts of their bodies to clear any debris from the previous item they touched. When the fly is walking about in any environment, there are tiny particles that stick to its feet. It’s much like when you walk around barefoot — even if the floors have just been cleaned, there are still going to be tiny particles that stick to your soles. Now, imagine walking in a bowl of pasta. You’d want to clean up too!