Shoppers have expressed their alarm at seeing a family of black mustelids emerge from a drain and walk down the high street in a town. 

The creatures were heard in a drain in North Street, Horsham.

They emerged and then crossed the main road towards Norfolk Street in the afternoon on Saturday, July 8. 

The sighting sparked confusion as residents were unsure whether they were pet black ferrets or a family of wild mink, both from the mammal group called mustelids - which also includes animals like stoats and weasels.

Sam Everley, from Horsham, shared the image on Facebook. 

He told The Argus: "They appeared out from the drain where the circle is and then went up Norfolk Street." 

The Argus: The mustelids emerged from the drain and made their way across the roadThe mustelids emerged from the drain and made their way across the road (Image: Sam Everley)

On social media, many said they believe the animals are mink, with some referring to a sighting of one of the creatures in Horsham Park recently.

Writing on Facebook, Michelle Henderson said: "I believe in the seventies there was Whites Bridge mink farm in Sedgewick Lane. A group of animal rights activists went in and set a load free. They have been in Horsham ever since."

Though ferrets are typically lighter in colour, black ferrets do exist. 

Their fur can be dark, jet black from head to tail with no white visible on the face. 

A spokeswoman for Horsham District Council's parks and environmental health team confirmed the creatures are mother mink and its kittens. 

After previous sightings of mink in Horsham, Sussex Wildlife Trust said:  “The American Mink is a non-native invasive species, originally brought here to be farmed for its fur, but now living wild across Sussex and the UK.

“It is fairly common and widespread. Being semi-aquatic, it is usually seen in or close to water, where it is sometimes mistaken for the native Otter.

“Mink are voracious predators and highly damaging to our native wildlife, particularly water vole and kingfisher, as mink can squeeze into their riverside burrows leaving them with no means of escape.

“From a conservation perspective, mink trapping is necessary and since it is illegal to release them once caught, they must be humanely dispatched.

“Effective control can be difficult without taking a broad, landscape scale approach as mink travel easily along river corridors, and readily re-colonise.”