Although dogs use physiological methods to detect scent trails, they apply these methods differently depending on the environments in which they are tracking. A scent results from the individual odour of a person being tracked or through an environmental disturbance odour that results from the physical movements of the person being tracked. The ways in which dogs track an individual, vegetative and track scent can vary depending on circumstances. Specifically, scent tracking ability of a dog depends on whether or not an individual deposits their scent in the air or on the ground.