i used to bicycle up the cross-canada trail behind bells corners through stittsville and out to carleton place fairly often, and there's tons of deer back there. it's less that we humans don't fall into their "natural prey" like you'll hear some naturalists suggest (either out of some remnant creationist intuition, or out of an attempt to not create panic), but when there's that much good food to eat, skinny humans full of leather and cotton are less appetizing.

you move pretty quickly on a bike like that when there's no traffic to worry about, but you can hear things. and you can feel yourself being stalked, somehow. they're back there, and if somebody were to really look for them they'd no doubt be shocked by how many.

melanistic pumas are not supposed to exist outside of south america. but, it strikes me as a little bit daft to rule out the possibility altogether. those genes gotta be in there somewhere, waiting for the right mutation.

that's clearly a house cat, though.

it does look like a house cat - due to the ears, and the grooming behaviour. and some of the side shots look like a house cat's face.

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.