Which tigers do you think live longer, zoo tigers or circus tigers?

Apparently, circus tigers seem to have a longer lifespan.

Why?

Maybe because circus tigers are more stimulated by their daily training. Training keeps these animals happy, giving them a job to do and the feeling that their lives have meaning. Circus tigers rarely pace in their cages and have a strong bond with their trainers. Neither trainers nor tigers are afraid of each other because they are almost always together.

Zoo tigers, on the other hand, tend to spend all day doing nothing but resting . These animals don't receive vigorous daily trainings. They simply have nothing to do. There may be a bond between caretakers and these tigers, but probably not as strong as that of circus tigers and their trainers. Zoo tigers are bored...

Average large zoo cats tend to live to eight to ten years. Many circus tigers tend to live to fifteen to sixteen years, some live more than twenty years. I'm sure wild tigers are the happiest of all, but I thought this was a thought-provoking fact about how animals can live a longer, happier life - beyond just giving food and shelter.

This trivia comes from the book The Tribe of Tiger by Elizabeth Marshall Thomas.