In Honor of Dusty

My male Pomeranian, Dusty, was dead when I came home from work today. He had been fine yesterday, and went out this morning when I let him out, but he did seem a little sad when I left. I know I petted him and told him to be good. And he was. He was all curled up in the bathroom behind the toilet. He didn't make a mess or a fuss. He was a good boy. And I loved him. Do dogs know when they are going to die?
When my son was young, he found a dead dog in the woods behind our house. He had one of those tags on his collar that will identify him if you call the number. So we called and the owners said the dog had been just fine, old but fine until a day or two before. Then he rushed the owner and ran out of the fenced yard and dissappeared. He was all curled up in the woods when my son found him, just like he was taking a nap. Did he know he was going to die?