In a remarkable conservation success story, thousands of giant fen raft spiders are now thriving in the UK, thanks to a collaborative breeding program between the RSPB and Chester Zoo. These impressive arachnids, which can grow to the size of a human hand, were once on the brink of extinction due to habitat loss. But now, after their best mating season on record, an estimated 10,000 female spiders are flourishing in the wild.
The Path to Recovery: A Conservation Success Story
The road to recovery for the fen raft spider has been a long and carefully planned one. Fifteen years ago, these semi-aquatic arachnids were facing a bleak future as their wetland habitats disappeared. Recognizing the critical role these spiders play in aquatic ecosystems, Chester Zoo and the RSPB joined forces to launch a breeding program aimed at pulling the species back from the brink.
Hand-Rearing in Test Tubes
The conservation team faced a unique challenge: newly-hatched fen raft spiders have a propensity for eating one another. To ensure their survival, hundreds of tiny spiderlings were carefully separated into individual test tubes and hand-reared in a bio-secure breeding facility at Chester Zoo.
“It was a painstaking process,” recalled a member of the breeding program. “We had to feed each spiderling by hand using tweezers until they were large enough to be released into the wild.”
This labor-intensive approach paid off. Between 2011 and 2013, thousands of hand-reared spiders were released into restored wetland habitats across the UK. A decade later, the results are astounding.
Record-Breaking Mating Season
This year marked the best mating season on record for the fen raft spiders. The RSPB estimates that there are now 10,000 breeding females living in the wild – a figure that seemed unimaginable just a few years ago.
“We’re super proud to be part of this conservation breeding rescue program,” Chester Zoo announced. “You can’t miss these spiders – they grow to be the size of your hand!”
Walking on Water: The Fen Raft Spider’s Unique Abilities
The fen raft spider, also known as the great raft spider, boasts some impressive abilities. Their long legs allow them to gracefully skate across the surface of the water, using the tension to hunt aquatic prey. A series of tiny hairs on their legs and body help them to stay afloat.
- Appearance: Chocolate-brown body with distinctive cream stripes
- Habitat: Unpolluted fens and marshes across Europe
- Size: Leg-span can reach 70mm – about the width of an adult palm
Despite their impressive size, fen raft spiders are harmless to humans. In fact, their presence is a sign of a healthy wetland ecosystem. As top predators in their aquatic habitat, they help to keep populations of other invertebrates in balance.
A Bright Future for Britain’s Giant Spiders
The success of the fen raft spider breeding program is a testament to the power of conservation partnerships. By working together, the RSPB, Chester Zoo, and other members of the British and Irish Association of Zoos and Aquariums have brought this spectacular species back from the edge of extinction.
“This is a huge conservation success, both for the spiders and the wider habitat restoration driving their recovery,” noted David Clarke of London Zoo’s Friendly Spider Program. “And more natural biocontrols out there are only a good thing.”
As fen raft spider populations continue to grow and expand, they serve as a symbol of hope in the fight to protect our planet’s precious wetland habitats. With ongoing conservation efforts, these extraordinary arachnids can once again thrive in the wild – a true success story for British biodiversity.
