Giant spiders the size of a human hand have had a record breeding year in the UK following conservation efforts.

A decade ago, Chester Zoo released thousands of fen raft Spiders after the species was found to be in terminal decline.

The zoo has now revealed there are more than 10,000 breeding females across the country — an all time high for the arachnid in the UK. 

Chester 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!”

While they may look scary the fen raft spider is harmless and plays a vital role within healthy aquatic ecosystems, the zoo said.

Fen raft spiders are semi-aquatic spiders, named for their ability to run across the surface of the water to catch their prey.

Fen Raft Spiders actively hunt their prey instead of building webs to catch their next meal. 

Their legs are covered in tiny hairs that detect the slightest of vibrations on the water’s surface which they can run across to capture their prey. 

Their diet includes other spiders, damselflies, dragonfly larvae and pond skaters, and they will even catch fish and tadpoles. 

However, 15 years ago, the species almost became extinct after the destruction of its wetland home.

In order to save the species, the zoo set about rearing hundreds of baby spiders in individual test tubes as part of a collaborative conservation breeding rescue programm in partnership with the RSPB. 

The RSPB estimates there are 10,000 breeding females across the UK — the best year on record.

Chester Zoo said: “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!”

RSPB Mid Yare nature reserves site manager, Tim Strudwick, said: “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. 

“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!”