Do dog's understand death? When our old guy Nitro passed 8 years ago (we had him put down at home in my arms). They told us that it was important for Ace and Orion to see Nitro after he passed and said that they'd come up to him, sniff him and walk away. They were right and did exactly that, except Ace went one step further and gave him a kiss on the face. I sight that I'll never forget. Then they carried on like it was ok from that point on. When Orion passed in January it was so sudden and chaotic that us wisking him out of the house in the middle of the night to try to hopefully get him to the vet in time, we forgot about one thing, Ace. It all happened in front of him and then we came home without Orion. It nearly killed me to watch him night after night, week after week look for his litter mate of nearly 13 years. So having experienced two different sides of of death in dogs and seeing how calm Ace and Orion (the one that passed in Jan.) were, my answer is yes, Dogs understand death. In other animals or humans.