Robert Guest contacted The Gazette this week to say he fears people will be put off making the most of the countryside if they think there's a possibility of an attack.
The Dumfries-based enthusiast who spends most of his free time in the Galloway forests pursuing his interest in wildlife said: "In my experience, once someone reports a sighting, everyone thinks they're seeing things.
"I don't believe there are large cats here. I simply think people are letting their imaginations run wild and are hoping to see something so they can jump on the bandwagon."
Sightings of big cats have been reported from Kirkcowan, Carsluith, Dalbeattie and Whithorn in the past year but none were caught on camera.
Robert said: "For 15 years I have spent my weekends photographing birds and wildlife, often spending whole nights camping in the remotest parts of the forests in Dumfries and Galloway and I have never seen a big cat. I have seen foxes, badgers, deer - all of which startled me for a moment and then it becomes clear what they are.
"I truly believe the so-called sightings are one of these animals and the witness is hoping for something more exciting so lets their imagination take over. They are not mountain lions, panthers, pumas or jaguars."
One theory behind the large cat sightings is that different breeds of cats have mated and created unusually large feline creatures, which are now roaming in the forests around Britain.
But Robert feels that if this were the case, wildlife officers and walkers would have found more carcasses and have firm evidence of such things.
He said: "Everyone loves a good legend and if they can have a hand in creating a myth for the area, they will. But I think it could be dangerous to the tourism of the region as it may put folk off going out there.
"Maybe these things are simply fat cats. Has anyone suggested that yet?"
Forest rangers advise anyone who sees such an animal to stay away from it and report the sighting to them or local police.