however..
evolutionarily speaking, a cougar is basically a really big house cat. so, there's a lot of shared characteristics. for example, a cougar can't roar like a lion - and purrs like a house cat. it also grooms itself like a house cat.
there have been some cases of house cats growing very large, and it really wouldn't be out of the question for a population of feral cats to grow to the size of cougars over many generations if the right evolutionary pressures were present.
it's consequently hard to be certain - although i'd lean towards it being a house cat. it's definitely not a lynx or a bobcat, though.
if you could have gotten a shot of the tail, it would have been more clear.