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Why Do Flies Rub Their Hands Together?

If you have looked closely enough, you would have probably noticed that, after landing on your food or something else, flies start to rub their hands. Ever wondered why?

You’d be surprised to know this but flies rubbing their hands together is actually them washing up. Here, we look at the details of why do flies rub their hands together.

Why do flies rub their hands together?

Flies are insects with six legs, the majority of whom undergo several stages of development and feature a single set of wings as adults. While many fly species look identical, their tiny bodies often have drastic color and size variations.

Musca domestica, the typical house fly, is the current symbol for the taxon. Additionally, for a good reason: flies are prevalent all over the world, they are carriers for numerous diseases, and in landmark horror films like “The Fly” they have secured leading roles.

But, given their infamy, there is nothing about them that can be characterized as sinister, biologically speaking.

Understanding the rubbing behavior of flies

It appears like it is rubbing its ‘hands’ each time a fly rests. Several species of fly display the rubbing behavior.

However, it may be most noticeable in the behavior of house flies as they are widespread during hot seasons. Flies rub off their legs to keep them clean.

While it might seem illogical considering that almost each fly species has a putrid and dirt attraction, washing up is one of the activities that take their most time.

Flies remove chemical and physical deposits via the grooming cycle, and they clean the scent receptors. Maintaining the cleanliness of receptors plays a major part in the flight, hunting for food, finding partners for mating, and just about everything a fly does during its lifetime.

Flies as the torch-bearers of hygiene

If a fly lands near you, notice it closely. It’s not just rubbing its first pair of limbs.

It brushes its hands and wings as well. In fact, you will even find it rubbing together its hind legs.

The method of cleaning is so detailed and systematic that the University of Arizona has proposed including files as an example to educate children about appropriate hygiene in kindergarten.

This cleaning activity was found even in other species of insects. According to North Carolina University, completely evolved antennae (not found in flies) tend to be the greatest priority for insects when it comes to washing.

How flies clean

A fly that was soaked in dirt could expend greater than fifteen to twenty minutes washing its small body from the dirt. Since the fly can only use its legs to accomplish this job, an effective plan is required by it.

Scientists have found a series of cleaning motions in which flies wash themselves. They often start with head cleaning before arriving at lower priority areas of the body.

Why observing flies is useful for us

New work has shown that the neurotransmitters regulating the cleaning of each part of the body are hierarchically ordered. Therefore, the greater priority cleaning motions are performed first and as the washing process proceeds, the lower priority motions are combined.

New knowledge on activity patterns can help researchers determine the neural circuits that are critical for grooming in fruit flies, as per the head of the research team. The research was performed on fruit flies so that the researchers could understand better the ways insects execute movement transitions to create more complex behaviors.

The cleaning process of flies

It is paramount for activities of this degree of complexity that every move is performed in a specific order. By wrapping flies in dust and observing how they treated the mess, a postdoctoral researcher working at the Simpson’s laboratory named Andrew Seeds found that flies wash themselves by utilizing a consistent pattern of cleaning movements.

Seeds coated a fruit fly in dirt and then their reaction was awaited. The fly began to wash itself to restore its most essential sense by eliminating the dust from its eyes.

The fly then used its hind legs to cleanse the belly, wings and eventually the chest. The fly often took a rest from washing to get remove the collected dust on the legs which it used to clean.

Despite this apparently being the favored sequence, Seeds noticed some flies using another method. This shows that the cleaning process has no particular order and that it is quite flexible.

It reflected an indication that cleaning isn’t a series of movements in which each move affects the next one specifically. Scientists agree that, in majority of the cases, early moves in the cleaning process will disrupt later movements.

More reasons flies rub their hands together

So far, we have found that flies rub their hands together to perform a cleaning. However, that is not the only reason why flies rub their hands together.

The following are some other reasons for this.

Preparing to fly

The act of pressing their legs together helps flies to plan for the flight psychologically. The fly ensures the tiny hairs on the limbs and chest are matched through the grooming process.

In addition, the hairs serve as vestibulars, which provide guidance on the location of each limb. It does have a better starting lift and flight performance this way.

Injury check

The fly obtains detailed details about the current condition and readiness of each of its limbs via the rubbing motions. It could also inform the fly of any specific injury or harm.

You could see flies doing this before getting close to other flies because their touch could lead to a war.

Washing taste sensors

Flies step all over your food for a purpose. The fly feels your food over its feet.

You may have seen flies moving on fruit, halting at regular intervals and rubbing their hind limbs and forehead. As flies cannot eat hard food, they’re searching for a place where the food began to decay and consuming it is easier.

Until files start searching for a new source of food, they need to clean their sensors to enhance their precision. They also cannot eat it immediately, even though they encounter a fruit that is overripe.

Next, flies will decompose their food and do so by vomiting saliva that is stored in the stomach. This may be dangerous for you as flies bear a lot of unnecessary viruses from their dirty eating and breeding environment.

A fresh smell

While an insect drawn to waste bins and animal feces may seem odd, a fly shouldn’t have an overbearing smell. The fly is going to want to remove that scent even if just consumed some watermelon.

This is due to its innate predators which could recognize the smell and track it down. Therefore, for the survival of the fly, proper hygiene is necessary.

Walk every surface

What is the exact number of times you have you seen a fly on the ceiling of the house, and wondered how it could go on until it falls? It is probably more than a hundred times.

The fly succeeds in doing so not due to suction cups or sticky areas on its feet but instead via a vast number of tiny hairs on its body.

Heat dissipation

You will notice flies constantly searching for some shelter during the extremely hot days. They do this so that they can withstand the extreme temperatures.

Flies have yet another way to get through the hot days though.

They dissipate heat using their body hairs. These hairs have an additional surface to keep the heat off.

As they rub their legs, flies ensure that the hair is appropriately settled so as to maximize the heat dissipation process.


The final reason why flies rub their hands together is to protect themselves. When flies can be seen folding their legs over the mouth, the cleaning process extends.

The flies remove the hairs positioned on their heads by doing this.

Scientists have discovered that fibers mounted on the eyes of the fly can divert approximately ninety percent of the ventilation away from the eye surface. The hairs positioned on the head of the fly are obviously the most vulnerable and essential.

Therefore, the fly takes particular care of them as opposed to the hairs placed on their limbs.


When you observe a fly for a considerable period, like a supervillain in comic books, you will spot him rubbing together his “hands.” For this behavior, there is a straightforward reason that has little to do with meandering machinations: flies are cleaning themselves.

Or they might be preparing to fly, checking injury, washing taste sensor, dissipating heat, and more. All the information you need about ‘why do flies rub their hands together’ is provided above.