One need not believe in specific locations of heaven and hell in order to believe in a continued existence. But since we find it difficult to comprehend existence without a location to exist in then it's not unreasonable to give them a name. Call it heaven if that works for you.
If we consider the possibility of continued existence then , of course, the question arises as to whether only one species experiences this, or all. Or maybe as implied by some beliefs in reincarnation maybe the species doesn't matter as it's much the same sort of spirit powering each.
Since this tends to be all conjecture anyway maybe a possible position to hold is one where if the creature is aware of it's own existence maybe it has the ability to retain it's individuality after death, whereas those that do not just dissipate into the spirit realm no longer being an individual ?
But of course the best answer is either, "ask your father", or, "ask your mother", perhaps adding, "they're the ones with the brains in the family".