Specifically, for those animal companions that have real life counterparts (wolves, camels, whatever) is the expected lifespan meant to be the same? In the case of a wolf, google tells me that wolves generally will live 6 – 17 years depending on it being life in the wild, captivity, etc. Would this be the expected value for an animal companion, or because of the magical nature of Golarion, could they potentially have natural lifespans as long as their masters?
Of course, there's always the route of just casting some anti-aging spell on them, but I'm talking more from the side of a "naturally occurring" creature.
Best Answer
I can't seem to find anything for animal companions or familiars. In the core rules at least there seems to be nothing about their aging.
The closest i could find were a discussion about animal companions, and one about familiars in Paizo's forums, talking about their lifespans and how a familiar might live longer due to it becoming a magical beast. But there's nothing like that for animal companions.
So as far as i can tell, animal companions age regularly. I then started a search for anti-aging spells and have found nothing so far. Your best chance to keep your animal companion seems to have a friendly druid cast reincarnate on it.