Dog watches all the time in a way that no other animal does! Max the dog became depressed when he started to smell the breast cancer of his owner!
According to BBC Earth’s Secret Life of Dogs:
Dogs watch us all the time and read our body language like a sixth sense. They also smell our bodies for changes. Max smelt cancer in Maureen before any medical scans could pick it up. Dogs do this naturally and can be trained to pick up on tiny volatile chemicals given off by cancerous tumors. They can even be taught to alert diabetics to low blood sugar levels.
