Aging

Environmental & Science Education
STEM
Behavior
Biological Evolution
Edward Hessler

Lifespans vary with smaller critters living shorter lives (on average) and bigger critters living longer (on average). NPR's Robert Krulwich did a nice report more than a decade ago on the matter of size and longevity. A technical account published in 2005 may be found here.

Take domesticated cats and dogs. Cats are generally smaller and dogs generally larger but moggies tend to live longer than doggies. So what's up?

This Science (AAAS) video discusses this difference.