Article doesn&#x27;t address the question of whether a short lifespan is adaptive (i.e. whether current &#x27;limits&#x27; on lifespan have nothing to do with systematic barriers). One reason for this would be the need to pack in more generations under conditions where rapid change is necessary in order to compete.<p>The research on extra copies of tumor-fighter TP53 in elephants suggests that when the conditions are right, senescence can be rolled back. The fact that mammoths are extinct and elephants are next could mean there are downsides to this evolutionary strategy.