If you know that you have an inner spirit that will go
on after the death of your physical body then death is
nothing to fear ... and according to you if you don't
fear death then you have no proof of an inner spirit ...
That's a bit of a paradox really.
How do you know that other animals don't know about death?
Some people don't value the lives of others, or justify
killing them one way or another ... does that mean that they
don't know that they are going to die? (This relates to your
comments on animals killing after mating ... which is an
energy reclamation activity I would guess).
Do humans in the rain-forests of south america or the plains
of africa stress over their mortality ... or are they more
concerned with surviving the week ... or the day?
I don't think it's our brains that make us worry about these
things, but that we have mental capacity to spare in the
western world (otherwise we wouldn't be fiddling about on this
forum, would we?

)