Because the beaver is nocturnal, sightings are extremely rare and the reserve said it was not promoting it as a visitor attraction but rather celebrating what its discovery meant for the site.
In other parts of the UK, beavers have been reintroduced into the wild after the government gave its approval earlier this year.
“Wetlands are some of the most threatened habitats in the UK,” Mr Spowage said.
“To have a beaver recorded here is a reminder of what’s possible when you restore nature at scale.
“It’s a moment of hope, not just for Pensthorpe but for wildlife across Norfolk.”