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Sticker of Horn fly
Bug card No. 0741 of 1,500

Horn fly

Haematobia irritans
Name means: “Irritans means annoying, because it bothers cattle so much.”
Eats: BloodFlies and mosquitoesHouses and farms6 legs

The horn fly is a small grey fly, about half the size of a house fly. It lives on cows and drinks their blood. When it is not eating, it likes to rest near the cow's horns, which is how it got its name.

Lives in
First from Europe, now also North and South America, on farms with cattle
Length
4 mm (0.16 in)
Top speed
about 5.7 km/h (3.5 mph)
Flying, estimate
Can it hurt you?
Can bite or sting
It is a biting fly, but it mainly bothers cows, horses, sheep and goats. Cows with many horn flies get itchy and sore.
What does it eat?
Both males and females drink only blood, mostly from cows. Its maggots grow in fresh cow pats and feed on tiny germs there.
For real!Photo of Horn fly
Picture by Scott Bauer. Public domain, via Wikimedia Commons.

How big is it?

How long is it?

Horn fly about 4 mm long (0.16 in)A grain of rice about 6 mm (0.24 in)
small enough to sit on your fingernailcould fly across a whole football pitch in 66 secondsmoves 400 times its own body length every second

How big is Horn fly compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

How fast is it?

cool stuff

Fun facts

1

A horn fly can stay on the same cow its whole life. Only the mother leaves, to lay her eggs.

2

The females drink blood around 40 times a day, the males around 20 times.

3

The mother lays her eggs in cow poo while it is still fresh.

4

Many flies sit together on a cow, all facing the same way as the cow's hair.

5

It can go from egg to grown-up fly in only about 10 days.

you asked

Most asked questions about Horn fly

?Do horn flies bite people?

They bite cows, and sometimes horses, sheep and goats. They live on their animal host all the time.

?Why is it called a horn fly?

Because it likes to rest around the horns of cows when it is not feeding.

?How big is a horn fly?

It is about 4 millimetres long, half the size of a house fly.

For bug experts

Scientific name
Haematobia irritans
Named by
Linnaeus, 1758
Group
Flies and mosquitoes
Family
Muscidae
Classification
Insecta > Diptera > Muscidae
Lives on
Europe, North America, South America

Where the facts come from

  1. Haematobia irritans (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Scott Bauer. Public domain, Wikimedia Commons. The round sticker of this bug is cut from the same picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at hello@bugwiki.app and we will fix it.

More from the same group: Flies and mosquitoes

Also at home here: Houses and farms