[drache]

it's an issue of huge complexity
I'd just like to add that just because one has consciousness, it does not necessarily mean one can always govern ones actions
there is fascinating research showing that even slime molds have decision making ability
we don't know what they base their decisions on - supposedly mostly food needs
there are many humans that base their decisions on primitive instincts without any awareness
and there are those of us, who, through practice have sharpened their awareness sufficiently to understand that control is just a thin veneer
any time something can alter our perception to the extend, that we base our decisions on erroneous info
this happens in small ways most of the time, but throw in a few oddballs in terms of upbringing, traumatic events, or genetics and it can show up in bigger ways
I doubt that generally animals kill "for fun"
I believe that that is learned behavior and often it is human's idea of fun
we've trained them to kill
of course there is no reason either to suppose that animals are always "sane"
we've all seen animals who for reasons of upbringing, traumatic events, or genetics are not quite right, or worse
we all live in this world