Pawprints found in the north coast area of Northern Ireland were probably made by a member of the mountain lion family, the USPCA has said.
The animal is thought to be a young female puma
The animal welfare charity and police have been searching the area since Friday following reports of a big cat being spotted.
People have been warned not to approach the animal which is believed to be in the Portrush, Portballintrae and Bushmills area.
There have been up to 17 sightings of the animal, but the rough terrain has made it difficult to capture.
However, police have made plastercasts of pawprints found in the area and these have been studied along with measurements and eye-witness reports by experts at Belfast Zoo.
The USPCA's Stephen Philpott says they spent Tuesday examining the information they had gathered and now believe it may be a young female puma.
"To the best of our ability and as far as we can say it is a member of the mountain lion family, most likely a puma," he said.
Mr Philpott added there were so many sightings of the animal because it does not yet feel safe in its surroundings and that efforts to capture it will continue.
"It will pick a spot it is comfortable with, feels safe in and then we'll never see it again," he added.
Food placed at various locations as bait has shown signs that the animal has been there.
Animal welfare workers believe the cat may have escaped from a private collection.
It is not an offence to own such an animal in the province but the animal could prove dangerous if it is cornered.