Orcs were considered adults anywhere between 11 and 14 years of age. Orcs are considered middle-aged at 17, and old at 23, and finally venerable at age 35. The average Orc seldom lived longer than 40 years even if it managed to avoid violent death. It was unheard of for an orc to live longer than 45 without magical aid. Orcs had descended from the first elves that Morgoth approached before the other Valar had found them.
Morgoth tortured and ruined them. They are essentially bastardized elves since Morgoth could not create life on his own. Orcs live in darkness most notably deep inside mountains. They are excellent tunnel builders who shun the sun whenever possible because the light burns them. Morgoth bred the Orcs at a time when Middle-earth was still shrouded in Darkness.