Cave spider found at RSPB Minsmere. Pic by Jon Evans

An elusive cave spider has enticed visitors to a north Suffolk nature reserve for a rare glimpse of a creature which normally cannot be seen because it lives in the dark.

Cave spider found at RSPB Minsmere. Pic by Jon Evans

The spider discovered at the RSPB reserve at Minsmere has a body no longer than 15mm long, is among one of the largest spiders in the UK.

Cave spiders live in total darkness and are usually found in sites with no daylight such as cellars, long tunnels and caves – hence their name. They eat woodlice, flies and other small insects

Ian Barthorpe, from RSPB Minsmere, said: “Although cave spiders are probably not uncommon, because of their habitat requirements of total darkness they’re not often seen and so are very under-recorded. No-one really knows how many we have in the UK, so finding one here at Minsmere is a real treat.”

The spider was discovered in a shed close to the reserve’s visitor centre almost two weeks ago, but RSPB staff have been trying to verify the species before publicising the sighting.

The female spider is guarding a white, cotton wool-like egg case containing up to 300 eggs. She will watch over the egg case until her death, then next spring the baby spiders, called spiderlings, will emerge.

Visitors can request a personal viewing at the reserve’s visitor centre.

Mr Barthorpe said: “This spider wont be around for much longer – she’s done all the hard work and will soon die – so anyone who wants to see her better come soon.”