The average or expected lifespan of Hobbits, Men and Dwarfs is easily found but I can find no definitive answer for the 'expected' lifespan of an Orc. All I can find so far is, 'unknown'. Answer In the 10th volume of The History of Middle-earth (specifically in the "Myths Transformed" essay) it's written that Orcs had short lifespans in relation to the Númenóreans , which would mean that they weren't immortal. But at least Orcs could live a long life. The proof for that is Bolg , who died 140 years later than his father, Azog . Of course it may vary among different breeds of Orcs.