Dogs pant a lot primarily to cool down because unlike humans, they cannot sweat effectively through their skin due to their thick fur. Panting allows dogs to rapidly exchange hot air from their lungs with cooler external air, speeding up the evaporation of water from their tongue, mouth, and upper respiratory tract, which helps regulate their body temperature and cool them down effectively.

Additionally, dogs may pant due to other reasons such as:

• Physical activity: panting increases oxygen intake after exertion.

• Excitement or happiness: panting can accompany enthusiastic emotions.

• Stress or anxiety: panting may increase during stressful situations like vet visits or loud noises.

• Medical issues: certain health problems like heatstroke, heart or lung diseases, hormonal disorders such as Cushing's disease, or allergic reactions can cause abnormal or excessive panting.

• Breeds with flat faces (brachycephalic breeds) may pant more due to breathing difficulties linked to their anatomy.

Hence, while panting is a normal cooling mechanism and emotional expression in dogs, excessive or unusual panting might indicate anxiety or health problems needing veterinary attention.