Yes. Since the volume of an organism increases with size faster than the surface area, larger animals are far more effective at retaining their body heat (great

Yes. Since the volume of an organism increases with size faster than the surface area, larger animals are far more effective at retaining their body heat (greater volume stores more heat while a small surface area dissipates less heat). This in turn means less metabolic activity which means a longer lifespan based on our research of caloric restriction and it's impact on human longevity. However, there are much bigger animals that don't live anywhere near as long so this is unlikely to be a significant contributing factor.