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Sticker of New Zealand mud snail
Bug card No. 0961 of 1,500

New Zealand mud snail

Potamopyrgus antipodarum
Eats: PlantsSnails, slugs and wormsPonds, rivers and shoresNo legsNot an insect, but a bug cousin

The New Zealand mud snail is a tiny water snail, often smaller than a grain of rice. Its shell is long and pointy, in grey or brown, and it has a little lid to shut its door. It comes from New Zealand, but it has hitched rides all over the world.

Fun fact: this one is not an insect at all, it has no legs! But kids find it on every bug hunt, so it lives in Bug Wiki too.
Lives in
Native to New Zealand, now also in Europe, Australia, Asia and North America, in streams, rivers and lakes
Length
0.5 to 1.2 cm (0.2 to 0.47 in)
the height of the shell
Top speed
about 0.02 km/h (0.01 mph)
On foot, estimate
Can it hurt you?
Harmless
Harmless to people. But it is a big problem for rivers, so always clean your boots and nets before going to another river or pond.
What does it eat?
It grazes on the tiny bits of algae and old plant stuff that cover stones and mud underwater.
For real!Photo of New Zealand mud snail
Picture by Michal Maลˆas. CC BY 4.0, via Wikimedia Commons.

How big is it?

How long is it?

New Zealand mud snail about 1.2 cm long (0.47 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)
as long as 2 grains of rice in a rowneeds 3 minutes to cross a dinner table

How big is New Zealand mud snail compared to YOU?

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

How fast is it?

cool stuff

Fun facts

1

It has a little lid on its foot that it can use to close its shell tight.

2

In some American rivers there are more than 300,000 of them in one square metre.

3

It can live a whole day out of water, and up to 50 days on something damp, like a fisher's boots.

4

It can even come out alive after being swallowed by a fish or a bird.

5

It was first found outside New Zealand in London back in 1859, and now lives in almost all of Europe.

you asked

Most asked questions about New Zealand mud snail

?Why is the New Zealand mud snail a problem?

It spreads very fast and eats the food that local snails and water insects need, so fish have less to eat.

?How big is a New Zealand mud snail?

Its shell is usually about 5 millimetres tall, and at most about 12 millimetres.

?How can I stop mud snails from spreading?

Clean and dry your boots, nets and toys before you go to a different river or pond.

For bug experts

Scientific name
Potamopyrgus antipodarum
Named by
Gray, 1843
Group
Snails, slugs and worms
Family
Tateidae
Classification
Gastropoda > Littorinimorpha > Tateidae
Lives on
Australia and Oceania, Europe, Asia, North America
Also known as
New Zealand mudsnail

Where the facts come from

  1. New Zealand mud snail (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 Michal Maลˆas. CC BY 4.0, 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 [email protected] and we will fix it.

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