Brown bears at Katmai that make it to adulthood typically live to their mid-late 20s! in fact, Backpack here is just getting to the age where boars start to seriously contend for top spots in hierarchy, though he in particular is a laid back boar who tolerates other bears more than most boars of his age do.
The oldest bear we saw last season, as far as i am aware, is 477 Sara! She is an easy bear to identify, given that 9 of her 10 front claws are ivory-white, and she was first identified as an adult in 2001. Since she was not identified as a young adult/older subadult, we can assume she was 6 or 7 when she was identified, which would make her about 29 or 30 years old when we saw her last year!