Aging is mamal universal. It's a adaption to predation and I think the key would be to find a mammal that was not predated by dinosaurs. Something like whales.

Aging is mamal universal. It's a adaption to predation and I think the key would be to find a mammal that was not predated by dinosaurs. Something like whales. But even they have the predation damage. https://en.m.wikipedia.org/wiki/Blue_whale https://en.m.wikipedia.org/wiki/Blue_whale