do flies sleep

Do Flies Sleep? Facts That Will Surprise You

Have you ever been intrigued by the small and seemingly unimportant things in life — flies, for instance?

Many people may not find flies interesting, but they piqued the curiosity of some exceptional minds, curious to know the answer to this question: do flies sleep? The answer was yes, flies do sleep. Keep reading to learn more about where they sleep, how long, and more.

What Are Flies?


Flies are two-winged insects classified as members of the order Diptera. The order includes many species that use only one pair of wings to fly — hoverflies, craneflies, houseflies, horseflies, fruit flies, mosquitoes, and more.

Flies are known for their importance in pollination. However, they are more commonly known as a nuisance, responsible for the spread of many diseases like dengue, malaria, west Nile fever, encephalitis, yellow fever, and other infectious diseases.

Flies become more of an annoyance when they are large-sized or appear in large numbers. Besides spreading food-borne diseases, larger flies can also cause significant harm to cattle.

Do Flies Sleep?

Yes. Like humans, flies require sleep for normal functioning, fulfilling the requirement by sleeping at night.

Flies need polarized light, in the absence of which they cannot guide themselves visually. Thus, they are active during the day when polarized light is available and rest at night.

Besides, as flies are cold-blooded creatures, they function well during the day when there is warmth. So, they are active during the day, searching for food. As the sun sets, the dropping temperature slows them down.

Even otherwise, if the temperature drops too low, the flies acquire a dormant state where all their bodily functions slow down significantly.

However, mosquitoes, who are nocturnal creatures, do not follow the rule. Mosquitoes do not strictly need polarized light, as they have super-sensitive antennae and eyes that allow them to see at night. Hence, they are active at night, resting or sleeping during the day.

They may also take a few naps during the day, as staying too much in the sun can overheat their body, make them thirsty, and even result in death.

Where Do Flies Sleep?


Flies can sleep anywhere — on walls, tree trunks, corners, under grass and leaves, bath stalls, and flat surfaces. They have no preference — all they need is shelter from wind, rain, and cold.

However, they may prefer to sleep upside down, as laying on the ground exposes them to attacks from marsupials and other animals.

How Long Do Flies Sleep?

As their sleep cycle follows the circadian rhythm, flies can sleep at sunset and wake up at sunrise. So, flies can sleep anywhere between 8 and 12 hours a day.

Also, sleep requirement is directly related to the amount of energy used for brain activity and flying. Flies exhibit varied sleeping requirements at different life stages with different brain activities.

When the learning pathway is activated in flies, their brain uses up a lot of energy, and they need much more sleep.

Due to their increased activity in the summer, they sleep more. They sleep less during winter when they do not engage in much activity and may just flutter around.

What Do We Know About The Sleep Patterns Of Flies?

We now know flies sleep, and their sleeping patterns are much like that of humans.

Humans sleep in two stages — the light sleep stage, where we dream (also known as the Rapid Eye Movement (REM) stage), and the deep sleep (non-REM stage).

The University of Queensland conducted research that found that flies also have a two-stage sleep cycle consisting of light and deep sleep.

The circadian rhythm controls their sleep cycle, putting them to sleep when the sun sets and waking them up when it rises. Since flies are cold-blooded animals, their bodies can heat up under the scorching sun, so they take afternoon naps to cool off.

10 Fun Fly Facts That Will Blow Your Mind


1. Flies Can Live In Virtually Every Habitat

These diverse creatures can live in any habitat, as they are very adaptable. Flies are present on every continent of the world. A species is found in the incredibly chilly Antarctica as well.

2. They Taste With Their Feet

Besides having taste receptors in their mouth, flies also have receptors on their legs and feet. So, before using their mouth, they first rub their feet on the food to determine if it is worth eating.

3. They Do Not Have Teeth

Ever felt a mosquito bite? It is not the teeth, just the edgy mandible or sharp proboscis. This also means they cannot take solid food. They inject their tissue-liquifying saliva into the wound and suck the liquid with the help of the proboscis.

4. Most Of Them Beat Their Wings 200 Times Per Second

Flying is an energy-consuming task, and as the speed increases, the beat frequency increases as well. Some species can even reach up to 1000 beats per second.

5. Short Life Span But Multiply Quickly

They have a short life span, generally falling in the 5 to 30 days range. However, they multiply quickly, laying between 150 and 450 eggs in each batch, depending on the species.

6. They Are Quite Ancient

Flies can be traced back to 240 million years ago, the Middle Triassic period. It is highly likely that they were the first pollinators.

7. Drugs Can Affect Their Sleep Cycle

Just like in humans, chemicals also affect the sleep cycle of flies. Chemicals like cocaine, and caffeine, keep them alert, and alcoholic beverages and antihistamines make them drowsy.

8. Sleep Deprivation Can Have Deleterious Effects

Sleep deprivation can affect memory as well as brain development in baby flies.

9. They Contribute To The Food Chain

Some fly species lay their eggs on animal carcasses, helping decompose and release nutrients into the soil.

10. The World’s Biggest Fly

The adult timber fly is the world’s largest fly. It can reach up to 8 centimeters and is found in South and Central America.

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