Dogs likely have an instinctual sense that death is near based on their declining health.
Dogs notice the physical changes in their body as they decline such as weakness.
Alterations in their normal routine like increased rest can indicate to dogs something is wrong.
Owners' actions and emotions may signal to dogs that something is different.
Dogs don't understand the full concept of death and dying.
Dogs tend to focus on their immediate circumstances, not the future.
Living in the Moment
Dogs can't comprehend but they feel loved when owners comfort them.