I believe/understand it is mostly tied to reproduction and protection and development of offspring. Dogs (and many other animals) begin reproducing at a much y

I believe/understand it is mostly tied to reproduction and protection and development of offspring. Dogs (and many other animals) begin reproducing at a much younger age. Their genetics and genetic development evolved to support releasing a number of offspring to continue the species, but beyond that, the biological system had no longer value for the animal, and therefore genetics which enhanced longevity did not promote into the next generation. People rear children later, and when those children are growing, the human still plays a very active role in the development and maturity of those children. The genes which promoted longer life where therefore selected out as the children who were not reared with parents in reaching late 30s had a lower chance of survival. In addition, humans have a strong drive to live. Dogs, as they reach the end of their life, seem to be quite happy to find a nice place to lie down and die. They have no concept of "not dying". Not that they won't protect themselves, but they have no idea of medicine, of health, these are not concepts many other species can understand, and even if they could, there is not much they could do for them. With royalty and family, younger generations cared for the older, which increased lifespan beyond the generally accepted declining years. For example (I work in sleep), sleep begins degrading in our 30s, and this degradation is linked to all markers of aging and health. Our immune system weakens, our metabolic and cardiovascular systems decline, etc etc. Potentially there was/is some evolutionary selection here as well where the children who cared for their elderly were also more likely to survive longer, but I think that is a weak link. I'm not refuting the OP, but at one point genetics got us so far, and then lifestyle and environmental factors are now taking over. (edit) I originally posted this as a response the question about dog lifespan, but then realized it probably stands on it's own as a comment.