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Raft Spider

Raft Spider ©Ross Hoddinott/2020VISION

Raft spider

Scientific name: Dolomedes fimbriatus
The chocolate-brown raft spider inhabits bogs and ponds. It can be spotted sitting near the water, its legs touching the surface. When it feels the vibrations of potential prey, it rushes out to catch it, floating like a raft.

Species information

Statistics

Body length: 0.9-2.0cm

Conservation status

Common.

When to see

May to August

About

The raft spider is a large, chunky spider that lives around the edge of ponds and ditches, and on wet heaths and bogs. Adults sit at the edge of the water, or on floating vegetation, with their front legs resting on the water's surface in order to feel for the vibrations of potential prey. Using the surface tension of the water, they chase out on to the water to catch their prey, which will even include tadpoles or small fish. Raft spiders will also swim underwater, often diving beneath the surface when threatened.

How to identify

The raft spider is a large, chocolate-brown spider, with a pale yellow stripe running down each side of its body.

Distribution

Widespread, but scarce.

Habitats

Did you know?

The much rarer fen raft spider is similar to the raft spider, but is only found in a few places in the UK, including several Suffolk Wildlife Trust nature reserves.