Residents in the Drongan and Coalhall areas of Ayrshire are being urged to stay vigilant after reports of a black panther in fields between the two villages.
The warning was issued by Ayrshire Police at around noon on Friday, with the force adding that it was working with animal welfare charity the SSPCA to locate the animal, which might be injured.
A spokesman added: “The area is popular with dog walkers so care should be taken and if anyone sees the animal we would ask you not to approach it, but to contact police via 101, quoting incident number 0780 of Friday 19 October 2018.”
Rumours of big cats prowling the UK countryside have endured for years.
The animals – normally black or brown – have been seen in almost every county in Britain, from Cornwall to the tip of Scotland.
Sightings of mystery beasts have largely been blamed on the introduction of the 1976 Wild Animals Act, which curbed a growing fashion for exotic and potentially dangerous pets.
Some owners were thought to have freed their animals into the wild to avoid falling foul of the law.
The only native wild cat species in the UK is the Scottish wildcat, which looks similar to a domesticated tabby, but there have been calls to reintroduce the Eurasian lynx, thought to have disappeared from Britain around 1,000 years ago.
In March a Scottish wildcat nicknamed “the Beast” was captured on video by researchers in the Scottish Highlands who said the animal – estimated to measure four foot from nose to tail – was one of the largest recorded in the world.
In 2016 a zoo owner claimed sightings of the infamous Beast of Dartmoor are very likely to have been genuine glimpses of a pack of pumas released in the area during the late 1970s/early 1980s.
Benjamin Mee, who owns Dartmoor Zoo, spoke after Flaviu the lynx escaped the facility.
He claimed pumas roamed the region for more than 30 years until 2010, when he believes the entire pack was wiped out by the coldest winter on record.