People with arachnophobia may shudder at the thought, but a rat-sized, fish-eating spider is making “an incredible comeback” in the UK.

The marsh spider was threatened with extinction in 2010 due to loss of wetland habitat. But according to the Royal Society for the Protection of Birds (RSPB), the species is on track for its “best year” since 2012, when ecologists began reintroducing the arachnid to restored marshlands in southern England.

The aid organization recorded 12 “stable” populations in England – compared to three in 2010. According to the report, the female population is 3,750 individuals.

Swamp spiders prey on insects, tadpoles and fish, but are harmless to humans. One of the ecologists responsible for their return “jumps on the chair” when a spider invades his house. Despite this, Tim Strudwick, the RSPB’s reserve manager for the Mid Yare Valley, Norfolk, is delighted at the return of swamp spiders.

“It’s a great story,” he says. “Ten or more years ago, there weren’t many invertebrate translocations and most were failures. It’s great to see a translocation like this actually succeed.”

Image: Matt Wilkinson/RSPB Images
Main image: Jorge Fernandez Salas