Being mer, technically, do they have long lives like the Altmer and Dunmer? I am not sure how long Bosmer live. How long do Orcs live naturally? I know a lot of them prefer to go out fighting when they feel old, but if they didn't, how long would they be around?

The elder Scrolls often do not give this kind of information. Even with dunmer it's mere speculation, so who knows... but seems it'd be similar to that of humans. Just a guess though.

Never seen any evidence on this.
A lot of people assume they have shorter lives than other Mer and Men but don't provide support for the assumption.

I've heard estimates that they only sixty to eighty years. As I recall, they used to have much longer lifespans, then one of the Nordic gods took the Orc life expectancy and gave it to the humans since one of the Elvish gods shortened the human life expectancy........

I need to hunt around TIL to find exactly what I'm trying to say........