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Sticker of Giant water spider
Bug card No. 1899 of 4,939

Giant water spider

Megadolomedes trux
Eats: Other bugs and small animalsSpidersPonds, rivers and shores8 legsNot an insect, but a bug cousin

The giant water spider is one of the biggest spiders in Australia. It lives along slow creeks and waits at the water's edge with its front legs stretched out. When it feels a fish or frog moving in the water, it dives in to catch it.

Fun fact: spiders are not insects. Insects have six legs, spiders have eight. Everyone calls them bugs anyway!
Lives in
Eastern Australia, in New South Wales and Queensland, by slow creeks
Length
0.8 to 3 cm (0.31 to 1.2 in)
females about 30 mm, males about 8 mm
Top speed
about 2.1 km/h (1.3 mph)
On foot, estimate
What does it eat?
It catches small fish and frogs. It was even seen eating a grown-up tree frog.
For real!Photo of Giant water spider
Picture by Greg Tasney. CC BY-SA 4.0, via Wikimedia Commons.

How big is it?

How long is it?

Giant water spider about 3 cm long (1.2 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 5 grains of rice in a rowcould run across a dinner table in 1.7 seconds

How big is Giant water spider compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

The female is about four times as long as the male.

2

Long hairs on its front legs feel tiny ripples in the water made by fish and frogs.

3

After diving in, it can stay under water for up to 30 minutes.

4

The mother carries her egg sac around in her jaws.

you asked

Most asked questions about Giant water spider

?How big is the giant water spider?

The female's body is about 3 centimetres long, and her legs make her look much bigger.

?Can the giant water spider go under water?

Yes. It dives in to catch prey and can stay under for up to 30 minutes.

For bug experts

Scientific name
Megadolomedes trux
Named by
Lamb, 1911
Group
Spiders
Family
Dolomedidae
Classification
Arachnida > Araneae > Dolomedidae
Lives on
Australia and Oceania

Where the facts come from

  1. Megadolomedes trux (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 Greg Tasney. CC BY-SA 4.0, Wikimedia Commons. The sticker of this bug is drawn from this 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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More from the same group: Spiders

Also at home here: Ponds, rivers and shores

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