I was surprised to find my wife sleeping on the bed next to this exercise nut who doesn’t smoke or even drink socially. I wasn’t jealous because he’ll be dead in a decade. Not from me poisoning him, but because he’s a dog and they just don’t live too long.
If you like the idea of living for a long time, it’s good to be human. Why do we live so long? It depends on nutrition, environment and genetics. Basically, if your parents both lived a long time, you’re a woman, and you don’t get fat or smoke you’ll live a long time, as animals go.
It’s been this way for a long time if you discount deadly childbirths, infections, and traumas that were common until recently.
Most animals seem to get about the same number of heart beats over a lifetime and the bigger an animal is, the longer it takes to use up its allocated beats. Generally, the larger the animal the longer its life span probably due to the slower metabolism in bigger animals. For example, comparing a hamster to a horse, the heart rate is almost six times slower and the lifespan six times longer for the horse.
We’re a lucky exception to this rule of thumb. We live a lot longer than we should just based on our size. Maybe because we take a long time to mature, having more shots at creating offspring and being able to help rear the offspring of our offspring has favored longer lives for us. But nobody really knows why.