10 05/10/2011

Britain's Largest and Rarest Spiders Released Back into the Wild

Hundreds of endangered spiders have been released into the wild as part of a conservation programme aimed at stemming their decline in the UK.

The Fen raft spider was once commonly found in the wetlands of the Suffolk Broads, but the gradual destruction of its habitat led to it almost becoming extinct.

However, 400 of the rare arachnids, reared in a special bio-secure pod in the zoo, have been reintroduced to Carlton and Pevensey Marshes in Suffolk.

Karen Entwistle, one of our Lead Keepers said: "Fen raft spiders have become isolated to just a few pockets of habitat in England and their numbers have declined to preciously low levels. It would be difficult for the remaining populations to ever recover on their own.

“But, by rearing them and helping them through to adulthood just prior to their release, we’ve hopefully given them a much better chance of survival.”

Fen Raft Spiders reared at Chester zoo

For four dedicated months, Karen has spent four hours a day; four days a week, alone with the spiders in the special breeding facility at the zoo.

"I kept the spiders in separate test tubes so that they could not attack each other and I individually hand fed each of them, one at a time, with fruit flies. It was a very, very time consuming job but all very much worth it as it’s vital for the future of the species."

Fen raft spiders are one of only two British spiders that are fully protected by law and are named after their ability to float on water in the fens and wetlands where they live – thanks to their hairy legs.

Karen and our team hopes the work will help to significantly boost wild populations of the species – seen as one of the UK’s most endangered.