Keepers at Longleat are celebrating after the birth of no fewer than 67 rare wolf spiders.

Longleat is part an international rescue programme to try and save the Critically Endangered Desertas wolf spider.

It's thought that only around 3,000 Desertas wolf spiders survive in the wild within a small valley on the uninhabited Desertas Grande island, part of an archipelago off the south east coast of Madeira.

Keeper James Gotts, who is overseeing the spider project, said: "It's taken nearly two years to get the spiders to breed so this has been a major breakthrough and, with wild populations so threatened, for us to have had more than 60 spiderlings hatch out is a significant boost to their survival chances."

As well as being one of the rarest wolf spider species, Desertas wolf spiders are also among the largest with a legspan of up to 13cms.

"Historically there have been no native mammals on the island so the spiders are effectively the apex predators," said James.

"However, the recent expansion of an invasive grass species into the valley where the spiders live, has prevented them from being able to burrow into the ground to make their nests and their numbers have declined precipitously," he added.

Longleat is one of seven collections worldwide partnering with Bristol Zoo and the Portuguese government on the conservation programme.

The plan is to raise the spiderlings to adulthood and then release them back into the wild to boost native numbers.

"As well as setting up our own breeding colony the spider laboratory in our Animal Adventure area is assisting with research into this little known species as well as helping to raise awareness of their plight," he added.

The tiny baby spiders are being looked after in a carefully-controlled environment and staff are even monitoring temperatures on the island to ensure conditions in captivity mimic those in the wild.