Longevity and animal scale
Larger scale in animals of the same shape would reguire greater blood pressure. This might negatively affect longevity. However, a larger heart requires a slower heart rate. The empirical evidence indicates that the mammalarian heart is good for about a billion beats regardless of animal scale. The slower heart rates of larger scale animals more than compensates for any negative influences of scale on longevity. The data indicates that animal longevity is roughly proportional to the 0.6 power of animal scale.