Pet turtles may live up to 100 years of age in exceptional circumstances, but the average lifespan of most pet turtles is 40 to 50 years, according to About.com. The largest land tortoises live even longer, reaching up to 250 years of age, according to the BBC.
The BBC explains that a rare giant Seychelles tortoise, named Jonathan, is likely the oldest living land animal. His keepers believe that Jonathan is 182 year old. The years have not been kind to the tortoise, who is now almost completely blind due to cataracts. However, the tortoise still possesses a good sense of hearing.