Hmmm, well they would have to understand the concept of death and I am sure they do. If a prey animal didn't fear death than it wouldn't run and hide when it sees a hawk/it's shadow. A lion most surely know what death is because they kill/eat animals all the time. A animals goal is to reproduce as much as they can before their death to ensure their genes carry on.
For them to do that they would have to have a theory of mind. The bad news is most animals do not have a theory of mind. The only animal that has been shown to have a theory of mind are the elephant and the dolphin. So as long as the animal that you are talking about is not a dolphin or an elephant they most likely don't know that they are going to die.
It would be hard to know whether they do.
Many species certainly are aware of the death of others.
And of course, all animals have the instinct to avoid death. But what does instinct mean? It means behavior that is practically automatic. It does not necessarily mean that animals know that they can die.
Animals, I don't think, are aware of their mortality . They fear being hurt and pain from instinct . No real way to know so mine is a guess .
Serious thought has gone in to the behaviour of elephants. When they come across a dead elephant, they stay near the spot for ages and manipulate the bones as if paying respect. Scientists are now fairly sure that they may be aware of their own mortality.
I don't think animals know they are going to die "someday" (as in some far off future event) . However I think that when they are very sick, they know it. And when they are dying, they know it.
like humans, we know that we're gonna die, do they know this thing
