Arachnophobes in the UK might find their fears amplified as giant Fen Raft spiders, capable of growing to the size of a human palm, experience a population boom. Nearly a decade after Chester Zoo’s intervention to save the species from near extinction, these spiders are now flourishing across the country.
In 2014, Chester Zoo released thousands of Fen Raft spiders back into the wild in partnership with the Royal Society for the Protection of Birds (RSPB). At that time, the spider population had dwindled to critical levels, prompting conservationists to act. Today, there are over 10,000 breeding females, marking an incredible recovery for the species. Chester Zoo celebrated the success, sharing, “We’re thrilled to see more than 10,000 breeding females thriving after the biggest mating season on record!”
In collaboration with RSPB, Chester Zoo undertook an intensive breeding program to save the spiders. In 2011, zoo staff carefully raised hundreds of baby spiders in individual test tubes, meticulously feeding them with tiny flies in a bio-secure facility. Once strong enough, the spiders were reintroduced into their natural habitat, which the zoo’s partners worked to restore, creating an ideal environment for their survival and growth.
Despite their intimidating size, Fen Raft spiders pose no threat to humans. Identified by a distinctive white stripe along their body, these spiders have a unique hunting method: instead of using webs, they rest their front legs on water surfaces, detecting prey through the vibrations using tiny leg hairs. They play an essential role in maintaining aquatic biodiversity, particularly in the ditches of grazing reserves.
Tim Strudwick, RSPB’s Mid Yare site manager, emphasized their ecological importance: “These spiders contribute significantly to the aquatic diversity in our reserves and are fascinating to observe.”
Through years of dedicated conservation work, Chester Zoo and RSPB have successfully revived a species once at the brink of extinction, turning the Fen Raft spiders’ story into a landmark achievement in British wildlife preservation.
