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Sticker of Common shiny woodlouse
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Common shiny woodlouse

Oniscus asellus
Eats: Leftovers and dead thingsWoodliceGardens and meadows14 legsNot an insect, but a bug cousin

The common shiny woodlouse is a flat, shiny, grey-brown little crawler with lots of legs. It loves damp, dark places, especially under old rotting wood. It is not an insect at all: it is a land cousin of crabs and shrimps.

Fun fact: woodlice are not insects. They are crustaceans, cousins of crabs and shrimps, that live on land.
Lives in
Northern and western Europe, and brought to North America, under logs, stones and in gardens
Length
1.6 cm (0.63 in)
up to this size
Top speed
about 0.17 km/h (0.11 mph)
On foot, estimate
Can it hurt you?
Harmless
Harmless. It cannot bite or sting. Hold it gently and put it back somewhere damp.
What does it eat?
It eats rotting wood and dead leaves, which helps clean up the garden. After it changes its skin, it often eats the old skin too.
For real!Photo of Common shiny woodlouse
Picture by Katja Schulz from Washington, D. C., USA. CC BY 2.0, via Wikimedia Commons.

How big is it?

How long is it?

Common shiny woodlouse about 1.6 cm long (0.63 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)
as long as 2.5 grains of rice in a rowit has about 14 legscould run across a dinner table in 21 seconds

How big is Common shiny woodlouse compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

Unlike some woodlice, it cannot roll itself up into a ball.

2

It changes its skin in two halves: first the back half, and a little later the front half.

3

The pale patches on its back are little stores of calcium that it uses to make its new skin hard.

4

Babies are bumpy with orange markings, so they look quite different from the smooth grown-ups.

5

It is one of the woodlice people see most often all over the world.

you asked

Most asked questions about Common shiny woodlouse

?Is a woodlouse an insect?

No. Insects have six legs, but a woodlouse has fourteen. It is related to crabs and shrimps.

?What does a woodlouse eat?

Mostly rotting wood and dead leaves. It helps turn old plant bits back into soil.

?Can the common shiny woodlouse roll into a ball?

No, it cannot roll up completely. That is a trick of the pill woodlouse, a different kind.

For bug experts

Scientific name
Oniscus asellus
Named by
Linnaeus, 1758
Group
Woodlice
Family
Oniscidae
Classification
Malacostraca > Isopoda > Oniscidae
Lives on
Europe, North America
Also known as
Common woodlouse

Where the facts come from

  1. Oniscus asellus (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 Katja Schulz from Washington, D. C., USA. CC BY 2.0, 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.

More from the same group: Woodlice

Also at home here: Gardens and meadows