Their population was revived over a 15-year period
Ten years ago, thousands of rare spiders the size of rats were released across the UK following a 15-year long conservation project led by Chester Zoo.
Now, the zoo has issued an update on their progress, announcing that there are now 10,000 breeding females that have just had their biggest mating season on record.
The Fen Raft Spider was on the verge of extinction in the UK just 15 years ago, but now – thanks to the hard work of conservationists – up to 3,750 breeding females have been recorded at 12 sites in Norfolk alone.
The spider’s numbers had dwindled just over a decade ago due to a lack of wetland habitats.
However, thanks to a remarkable project at Chester Zoo to hand rear thousands of the spiders in individual test tubes to prevent cannibalism and reintroduce them into the wild, they are back.
The spider can range from the size of a human’s palm to the size of a rat.
A spokesperson from Chester Zoo told Cheshire Live: “While they may look big and scary to some, the fen raft spider is harmless and plays a vital role within healthy aquatic ecosystems. However, 15 years ago, they almost became extinct after people destroyed its wetland home.
“Our team delicately hand fed tiny flies to each of the hundreds of spiderlings using tweezers, day in, day out, for weeks on end in our bio-secure breeding facility. Eventually, the young spiders grew strong enough to be returned to their natural habitat , which our partners worked to restore, and we released them in their hundreds.
“Now, almost a decade and a half later, our friends at the RSPB estimate there are 10,000 breeding females across the UK , and they’re having their best year on record. We’re so proud of the part we’ve played in this incredible conservation success story, ensuring the survival of a species that was previously on the brink of extinction.”
Tim Strudwick, RSPB Mid Yare nature reserves site manager, said: “These spiders have an important role in maintaining the rich aquatic diversity found in the grazing ditches on our reserves. The females are impressive in size, but also beautiful they are truly special to see.”
In yesterday’s update the Zoo said: “Ten years ago we helped release THOUSANDS of GIANT spiders back into the UK!
“The fen raft spiders were bred right here at the zoo, and we’re super happy to report there are now more than 10,000 breeding females… and they’ve just had the biggest mating season on record!
“You can’t miss them, they grow to be the size of your hand! Honestly, you’re so welcome.”
Despite their noble cause, we doubt arachnophobes across the country will be thanking them.
The Fen Raft Spider is roughly the size of an adult male’s hand, and can spin webs as big as pizzas (25cm).
They are also semi-aquatic and can run across the water’s surface to capture their prey.
Their diet includes other spiders, damselflies, dragonfly larvae and pond skaters, and they will even catch fish and tadpoles.
Back in 2010, the spider was restricted to just three sites in the UK and only a handful of spiders remained.
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Efforts to improve the creatures habitat and damp weather in recent years are thought to have given the species a boost.
Site manager Tim Strudwick, told Mail Online that he was proud that the spider had recovered.
“The Fen Raft Spider is one of the UK’s rarest invertebrates and we are proud of the role our reserves and teams have played in its recovery,” he said.
“These spiders have an important role in maintaining the rich aquatic diversity found in the grazing ditches on our reserves.
“The females are impressive in size, but also beautiful – they are truly special to see.”
He added: “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.”
Despite the Fen Raft’s bite being poisonous and painful, they are not considered dangerous and a nibble from one of them would only lead to minor pain and swelling.
