Dogs and their Sensitivity to Smell

The Nose Knows Dogs excel at all kinds of detective work because they are superior sniffers (see Lifesaving Sniffers). Their sense of smell is 10,000 times more sensitive than a human’s. That allows them to sniff out faraway odors that humans can’t smell at all, like tiny bits of animal scat. Droppings give off odor molecules, tiny particles that carry scents through the air. When a dog sniffs, cells inside its nose called scent receptors capture these molecules and send signals to the brain. The brain then determines what the smell is from (see How a Dog Uses Its Nose).