My dog knew.. She was border trained and never left the yard for 14
years. The day before I took her out we were in the back yard with the
kids, it was snowing and she barked and looked at us. She took us on
about a three mile walk through the woods and fields, came home and
curled up by the couch.. She knew. I held her in my arms for about a
half hour after, crying, the vet let me stay there on the floor with her
until I could get up and walk..