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Sticker of Darwin's bark spider
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Darwin's bark spider

Caerostris darwini
Name means: “named in honour of the naturalist Charles Darwin”
Eats: Other bugs and small animalsSpidersPonds, rivers and shores8 legsNot an insect, but a bug cousin

Darwin's bark spider is a small spider from Madagascar that builds the biggest round webs in the world. It hangs them right over rivers and lakes, where no other spider can. Its silk is the toughest natural material scientists have ever tested.

Fun fact: spiders are not insects. Insects have six legs, spiders have eight. Everyone calls them bugs anyway!
Lives in
Madagascar, in the rainforest of Andasibe-Mantadia National Park, over rivers and lakes
Length
0.6 to 2.2 cm (0.24 to 0.87 in)
females are much bigger than males
Top speed
about 1.8 km/h (1.1 mph)
On foot, estimate
Can it hurt you?
Harmless

Watch out! Read all about it on Venom Wiki →

What does it eat?
It catches insects that fly over the water. One web was seen holding 32 mayflies at once.
For real!Photo of Darwin's bark spider
Picture by Matjazgregoric. CC BY-SA 4.0, via Wikimedia Commons.

How big is it?

How long is it?

Darwin's bark spider about 2.2 cm long (0.87 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 4 grains of rice in a rowcould run across a dinner table in 2 secondsmoves 23 times its own body length every second

How big is Darwin's bark spider compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

The lines that hold up its web can stretch 25 metres across a river, longer than a swimming pool.

2

Its silk is more than ten times tougher than Kevlar, the material used in safety vests.

3

It lets out silk that the wind carries across the water to build a bridge.

4

Females are mostly black with white hairs and about three times longer than the males.

5

It was discovered in 2009 and named 150 years to the day after Charles Darwin's famous book came out.

you asked

Most asked questions about Darwin's bark spider

?How big is the web of Darwin's bark spider?

Its round web can be up to 2.8 square metres, and the bridge lines can stretch 25 metres.

?Why is it called Darwin's bark spider?

It was named after Charles Darwin, the famous nature scientist.

?Where does Darwin's bark spider live?

Only in Madagascar, where it hangs its webs over rivers and lakes.

For bug experts

Scientific name
Caerostris darwini
Named by
Kuntner & Agnarsson, 2010
Group
Spiders
Family
Araneidae
Classification
Arachnida > Araneae > Araneidae
Lives on
Africa

Where the facts come from

  1. Darwin's bark spider (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 Matjazgregoric. CC BY-SA 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 hello@bugwiki.app and we will fix it.

More from the same group: Spiders

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Also at home here: Ponds, rivers and shores

Widow skimmerDragonflies and damselfliesPhantom midgeFlies and mosquitoesEastern amberwingDragonflies and damselfliesMarch brownOther insectsGiant dobsonflyOther insectsWater scorpionTrue bugs and cicadas