How well do animals understand death?

I know that animals have the ability to understand when another animal is dead and that they are programmed to avoid predators if they want to survive, but do they understand that someday their life will end too?
As humans, we know that someday we will die. We don’t know when and we don’t know how, but we know it will eventually happen. Do animals understand this concept at all?
They see other animals die, but do you think they truly understand what has happened when they see another animal die?

I know that animals can grieve over the absence of someone they love very much, whether it’s a mother missing her child or a dog missing his owner, but I’m curious how well animals can relate to death as we understand it.

Here are some other questions to ponder:
– Do animals know when they are dying and even so, do they think this pain they are experiencing means their life is ending or could they think it’s something else?
– Do they know when they’ve come close to death, such as being chased/attacked and surviving it or getting really ill and surviving?

Any information or personal stories you’d like to share would be great. Thanks everyone. :]