@mister kitten,
I think that it is inherent in a living creature's nature to crave power of one form or another.
To take a controversial human example; you may argue that a hermit is the polar opposite of a power-craver, however, it is apparent that the hermit craves a different type of power (you may say an even greater and more focused power), namely, power over one's own life.
What do you think? Is it natural for living beings to crave power? Do all crave power? And what sorts of power can one crave (human or animal)?