Will pets make your life longer?

Many books claim that there are some benefits of having a pet for your healthiness(longer life,lower stress level,good personality,safeness,etc.),although some people don’t believe it. is this simply a rumor?. I know it must has some scientific basis on it,but I’m curious about how does it work(Physically,psychologically,biologically,or else?).
Is it only work on furry creature(dog,cat,rabbit,etc) or will it work on other creature as well?(fish,bird,snake,etc). I know that feeling will play a role on it,but there must be something else.