A semi-acquatic great or fen raft spider (Dolomedes plantarius) hunting its prey walking on the surface of water between brown dead leaves in a swamp
Fen raft spider (Dolomedes plantarius) hunt prey by skating across the water (Picture: Getty Images/iStockphoto)

In news you’d be absolutely delighted to read, giant spiders which create webs the size of pizzas could be in your back garden as you read this.

Well, if your garden has a fen, a type of wetland, at least.

Fen raft spiders are chunky arachnids that live on the edges of ponds, fens and coastal grazing marsh ditch systems, poking their front legs into the water.

But they’re not taking a dip here – they’re feeling for tiny vibrations made by their prey, which are fish and tadpoles.

Yes, you read that right. This is a giant fish-gobbling spider that can, according to the British Arachnological Society, even skate around the water to catch prey.

Fen raft spiders are easily one of the largest and rarest species of arachnids in Britain.

Their body is 22mm (0.87 inches) long with a leg span of about 70mm (2.8 inches) – females are about the size of a human palm. So, if you spot on in your house, you might need more than a mug to trap it.

Despite this, these creepy crawly kaiju were on the brink of extinction until 2010 as their wetland homes were destroyed by humans, sucking the fens dry so the water could be used for public use.

The great raft spider or fen raft spider (Dolomedes plantarius) close up
The beasty spiders were once on the brink of extinction (Picture: Getty Images/iStockphoto)

They were listed as endangered on the UK Red List of species of extreme rarity in 1991, the Fen Raft Spider Conservation says, and are protected by law under the Wildlife and Countryside Act (1981).

But thanks to conservation efforts, fen raft spiders are thriving once more in Norfolk and Suffolk, Discover Wildlife reported.

There are thought to be 3,750 fen raft spiders skittering around the Strumpshaw Fen in Norfolk alone.

Conservationists increased the number of sustainable spider populations to 12 by digging up more suitable habitats for them and, well, moving them there.

In 2011, there were only three populations – Suffolk, East Sussex and Swansea.

Ask anyone with arachniphobia, and this might not be the news they wanted to read. For local wildlife, however, this is just what they’d been hoping for, Tim Strudwick, the RSPB Mid Yare nature reserves site manager, told Disoicver Wildlife.

‘The females are impressive in size, but also beautiful – they are truly special to see,’ he said, really stressing that fen raft spiders are completely harmless to humans.

‘The spiders are only seen in the grazing marsh ditches and are fairly shy but are easier to see from June to September.

‘Walking along the meadow trail gives visitors at Strumpshaw Fen the best chance of sightings of the mature females and their glistening nursery webs, so now is the perfect time to make a trip to the reserve.’

Those webs, by the way, stretch about 25cm across – about the size of a pizza.

While their numbers are on the up, these semi-aquatic spiders remain classed as ‘vulnerable’ to being wiped out.

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