Do Flies Sleep?

Do Flies Sleep

Do flies ever sleep? Yes, flies require sleep just like humans. In fact, their sleep patterns are not that different from ours. They enjoy the warmth and daylight so this is the time they go about their business. Eating, mating, exploring, playing, and existing. Then at night, they need to rest and recharge just as we do.

According to studies, flies have the same proteins as found in the eyes of humans. These proteins are called TIM and PER and they regulate our circadian rhythms, which is a fancy name for our body clocks.

Tim and per are what tells you to sleep when it gets dark and then when sunlight hits the protein in the eyes it is time to wake up.

A day in the life of a fly consists of actively carrying out fly duties during the day which is mainly of feeding, mating, and naps if required. Then at night settling down for hopefully 12 hours sleep.

The Environment a Fly Lives in Effects Their Sleep

Flies generally are more active during the day in the light and sun as they prefer this over cold weather especially snow.

Depending upon where the fly is situated for example in hot or humid climates a fly will require more sleep.

A fly’s sleep just like humans can be affected by chemicals and drugs. For example, they can become drowsy if they ingest antihistamines or alcohol.

On the other hand, just like us, they will be wide awake if they happen to get a hold of some caffeine, cocaine, or other stimulating drugs.

Where Do Flies Sleep? (Do Flies Sleep in the House?)

Come sunset a fly will find a safe place to spend the night where ever they are at that time. So to answer the question Do Flies Sleep in the House? Yes, they do if that is where they are at their bedtime.

Depending upon a fly’s daily activities and weather conditions a fly may take short rests or naps during the daytime. Especially if they have not been getting enough sleep throughout the night.


When flies are in their habitat they should be in “OUTSIDE” they will find somewhere quiet and safe to sleep. Under rocks, in tall grass, hiding amongst twigs, or blending in with leaves. Other places you might find flies are fences, clotheslines, rafter in sheds or barns, even on electric wires.

The selection of a place to sleep also depends upon a few other contributing factors these include wind, rain, sun, and heat. Also what predators are around such as birds, small insects, reptiles, and small animals.

Luckily if predators approach a fly while it is sleeping it will likely wake quickly and fly away.


When flies sleep in the house you will find that they gravitate towards the higher parts of the house such as walls, ceilings, rafters, and above curtains and blinds. Other places would be dark surfaces so they can blend in and will not be spotted. Also crevices anywhere they can sit undetected.

Do Flies Sleep
Photo by the name is karupu

Do Flies Sleep at Night?

Flies do sleep in the dark! In fact, flies get most of their sleep throughout the night. Ideally, a fly would like 12 hours of sleep. (Wouldn’t we all!)

If a fly does not enough sleep during the night it will attempt to make up the sleeplessness the next day with short safe sleep periods.

Flies will start searching for a safe place to spend the night before sunset.

A study has shown that at night flies actually needed to be startled awake to get them moving. This shows that when in a safe environment a fly must sleep quite deeply!

Do Flies Sleep with Their Eyes Open?

Yes, flies sleep with their eyes open because they do not have eyelids. Flies are constantly cleaning their eyes with their feet to keep them clean.

Do Flies Sleep in the Winter?

Ever noticed how there are more flies around in warm weather?

This is because flies are cold-blooded this does not allow them to adapt to the winter weather. They become inactive and die during the winter months.

Not before they have left behind cocooned larvae though. These larvae will then wait patiently for the springtime when they will become adults. And so the fly life cycle starts again.

Do Flies Sleep image

Do Flies Sleep Upside down?

Flies have a great gripping function, so yes flies can sleep upside down! They are able to grip surfaces like glass and even hang upside down as they have sticky pads on the bottom of their feet.

A fly would choose to sleep upside down because the weather may not be favorable (windy, rainy, or very hot). They will hang upside down under a leaf or in amongst brush or twigs to keep warm, dry, or cool.

A fly may also choose to sleep hanging upside down because there is no safe place on or close to the ground to sleep. This could be because there are frogs, spiders, marsupials, small insects (dragonflies), or animals even birds if they are around. Flies will look for somewhere higher to get some shut-eye.

Do Fruit Flies Sleep?

Yes, fruit flies sleep. The sleep habits are similar to those of other fly species.

Interesting Fly Facts

  • It is believed that a fly’s life span is reduced by one third if they do not get the required amount of sleep! This is disturbing it our sleep patterns are similar to that of flies. Considering it is reported that over 65% of Americans are not getting the required amount of sleep each night!
  • When the larvae hatch in springtime they feast on the fresh nectar from the flowers in bloom. This helps to pollinate the plant life as the flies carry and spread it around while they drink.
  • Baby flies need more sleep than adult flies just like humans they need this sleep to develop and grow into adult flies.
  • There is a species of fly that is the size of a pinhead. This little fly is the only known pollinator of the cocoa plant! What is the cocoa plant? It is that wonderful plant that provides the world with chocolate!
  • There about 120,000 species of flies (wonder who counted them 🙂 ) Some of the ones you might know of are houseflies, blowflies, carrion fly, bluebottles, horseflies, and the fruit fly.
  • The common housefly has been reported to live for 7 to 30 days. Their place in the ecosystem as we know it is to mate lay larvae die and then the cycle begins again.

Final Word – Do Flies Sleep?

Have you ever seen a fly that you believe is sleeping? Why not just quietly watch the fly and not swat it? After all, it will not be around very long anyway – around 30 days at the most.

Ever think about how other animals sleep? Check out this page here I have written articles about the sleeping habits of all kinds of living creatures?

As always here’s to better sleep!

Do Flies Sleep – Video


Report from The University of Queensland – Flies sleep just like us!

Do Flies Sleep
Categorized as Animals

By Michelle D.

Meet Michelle, founder of Tip Top Sleep, a website dedicated to helping you achieve the best sleep possible. With over 50 years of combined experience in the realm of sleep, Michelle and her team provide easy-to-follow tips and strategies to help you feel better, function better, and live better through optimal sleep. Let us help you prioritize your sleep and discover the power of a good night's rest.