Trekkie_DFW

I was looking up why dogs don't live as long as humans, and I found a lot of very sophisticated-sounding answers about things like metabolism and the trade off between maturing and reproducing more quickly vs taking longer to develop but having a longer lifespan (the whole--live fast, die young thing), and that makes sense, but... I saw something on a show..a Korean rom com, of all things...about telomere length and aging, and after researching it, I want to know--isn't that the real cause of aging? Aren't the explainations we often hear about reproduction and metabolism missing the real reason why species have different lifespans? Or is that too simple (or inaccurate) an explanation? Thanks.