[slayed0]

Do these sources include premature end of life from accident/injury/predation? It seems, at least intuitively, that these factors would significantly drag down life expectancy for outdoor cats. However, I think it would be useful to see the estimates with these factors excluded (noted of course) to just compare life expectancy assuming death from natural causes.

[simcop2387]

I don't know of any sources, but wouldn't injury and predation actually be natural causes for these outdoor cats? Saying that they shouldn't be counted because they "weren't natural" sounds a lot like the No True Scotsman fallacy. We don't tend to consider predation and injury as natural causes in humans mostly because we consider ourselves the apex predator so there's nothing seriously that can prey on us. And injuries in humans are typically caused by accidents and not our natural state; in a cat however they can get injured by the prey they're hunting or the environment without it necessarily being an accident which I would consider a natural cause.