and this study will try to figure out why birds of the same body size and mass of mammals live longer even though they have a much higher rates of energy use (because one would think that the more you 'use' something, the more it would 'age', right? - which is the case with mammals bodies). They think that oxidative stress (see below *) and immune system response might be the key because although oxidative stress increases in mammals with age, it doesn't in birds (I keep on telling you, birds are SOOOOO much cooler than mammals!!!)
https://www.eurekalert.org/pub_releases ... 050119.php
* Oxidative stress is an imbalance between free radicals (bad things that cause cancer and other diseases) and antioxidants (good things that fight free radicals).