What biological aspects that cause one species to live longer than another species?

We’re not going to discuss about psychological aspects that contribute in longer lifespan such as stress-free environment, adequate nutrition, health care, social stimulation, living in captivity VS nature, etc. We’re going to see things from other fields/point of views.

Take this as simple example:
A small chihuahua can live far longer than a big St. Bernard since it requires less effort to sustain its heart and other vital organs, etc. A rat that is almost the size of a chi live no more than 2 years. The lifespan of an elephant could be as long as the average lifespan of human. Cold-blooded species could live longer due to decreased metabolic rate (let us ignore them for awhile and focus on mammal, for now). Etc,etc. There are many other argumentative examples that I couldn’t write all of them here.

So I want to hear your personal scientific explanation/opinions toward this matter. Please don’t just say it’s already in genetic. You could be as argumentative as you want.