# Housefly (*Musca domestica*)

> The housefly (Musca domestica) is a small grey fly, about 6 to 7 mm long, found almost everywhere people live. It feeds by sponging up liquids and decaying matter, flies at up to around 8 km/h (5 mph), and completes its entire life cycle from egg to adult in a week or two. Adults live only about two to four weeks and the species is of Least Concern.

- **Category:** Insect
- **Conservation status (IUCN):** Least Concern
- **Range:** Everywhere humans live, on every continent except Antarctica.
- **Canonical page:** https://globalanimalguide.org/animals/housefly/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Insecta
- **Order:** Diptera
- **Family:** Muscidae
- **Genus:** Musca

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Musca domestica |
| Diet | Omnivore (liquid and decaying matter) |
| Habitat | Almost everywhere humans live |
| Lifespan | Adults about 2–4 weeks |
| Length | 6–7 mm (about 0.25 in) |
| Top speed | Up to ~8 km/h (5 mph) in flight |
| Conservation status | Least Concern (IUCN) |

## Anatomy and flight

A housefly measures just 6 to 7 mm and weighs a tiny fraction of a gram, yet it is one of the most agile fliers in the insect world. It has a single pair of working wings, while the hind pair is reduced to club-shaped halteres that act as gyroscopes and let it change direction almost instantly. In level flight it moves at up to roughly 8 km/h (5 mph), and its large compound eyes, each built from thousands of lenses, detect movement so quickly that a looming hand is spotted long before it lands. Sticky pads on its feet allow it to walk upside down across ceilings and glass.

## Feeding and mouthparts

Houseflies cannot bite or chew because they have no jaws. Instead they use a soft, sponge-like mouthpart called a proboscis to soak up liquids, and they dissolve solid food such as sugar or dried residue by dribbling saliva onto it first. Their diet is broadly omnivorous, taking in anything from spilled drinks and rotting fruit to animal waste and decaying matter. Taste receptors on their feet mean a fly effectively samples a surface the moment it touches down.

## Life cycle and reproduction

Few animals breed as fast as the housefly. A female lays batches of around 100 to 150 white eggs, often several times in her short life, in moist decaying material such as manure, compost, or rubbish. The eggs hatch within a day into pale legless larvae known as maggots, which feed and grow before pupating and emerging as winged adults. In warm conditions the whole cycle takes little more than a week, so a single pair can give rise to enormous numbers in a season.

## Where houseflies live

The housefly is one of the most widespread insects on Earth, following humans to almost every inhabited place from the tropics to cool temperate cities. It thrives around farms, kitchens, markets, and waste, wherever warmth and decaying organic matter provide food and breeding sites. It cannot survive hard winters outdoors in cold regions, but heated buildings let it persist year-round. This close association with people is why it carries the name housefly.

## Houseflies and human health

Because houseflies move freely between waste and food, they can carry bacteria and other pathogens on their bodies and mouthparts, and are linked to the spread of illnesses such as food poisoning and dysentery. They transfer germs by landing, walking, and regurgitating saliva onto surfaces where we eat. Good hygiene, covered food, sealed bins, and fly screens are the most effective ways to keep numbers down. Despite the risks, adult houseflies live only about two to four weeks, so populations turn over quickly.

## Role in nature

For all the nuisance they cause indoors, houseflies and their maggots are important recyclers of decaying material, helping to break down dung and dead matter and return nutrients to the soil. They are also a ready food source for birds, spiders, frogs, and countless other predators. Their rapid breeding and short generation time have made them a favourite laboratory animal for studying genetics and development. The species remains extremely common and is classed as Least Concern.

## Frequently asked questions

### How long does a housefly live?

An adult housefly lives only about two to four weeks. Its full life cycle from egg to adult, however, can be completed in as little as a week in warm weather, which is why the flies appear in such large numbers.

### What do houseflies eat?

Houseflies are omnivores that feed on liquids and decaying matter, including spilled food, rotting fruit, sugar, and animal waste. They cannot chew, so they use a sponge-like mouthpart to soak up liquid and dissolve solids with their saliva first.

### How fast can a housefly fly?

A housefly flies at up to around 8 km/h (5 mph). It is not fast in a straight line, but its club-shaped halteres act as balance organs that let it turn and dodge almost instantly, making it very hard to swat.

### Why are houseflies so hard to swat?

Houseflies have huge compound eyes that detect movement extremely fast and process it far quicker than we do, so an approaching hand looks slow to them. Combined with their rapid, jerky flight and quick take-off, this gives them plenty of time to escape.

### Do houseflies spread disease?

Yes. Because they move between waste and food, houseflies can carry bacteria and other pathogens on their bodies and are associated with illnesses such as food poisoning and dysentery. Covering food, sealing bins, and using fly screens greatly reduces the risk.

### How big is a housefly?

An adult housefly is small, about 6 to 7 mm long (roughly a quarter of an inch). Females tend to be slightly larger than males, and the body is grey with four dark stripes on the thorax.

## Sources

- [IUCN Red List — Musca domestica.](https://www.iucnredlist.org/search?query=Musca%20domestica&searchType=species)
- [Animal Diversity Web — Musca domestica. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Musca_domestica/)
- [Wikipedia — Housefly.](https://en.wikipedia.org/wiki/Housefly)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/housefly/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.