Dogs like to be petted primarily because it feels good and provides both physical and emotional comfort. When dogs are petted, it stimulates nerve endings in their skin, especially in areas like the ears, chest, and belly, sending pleasurable signals to their brain. This physical touch triggers the release of oxytocin, the "love hormone," which fosters feelings of happiness, trust, and bonding between the dog and the person petting them. Additionally, petting mimics natural grooming behaviors seen in dogs' ancestors and social animals, reinforcing social bonds and a sense of security. This connection through petting also reduces stress and anxiety in dogs by lowering cortisol levels, making them feel safe and loved as part of their "pack".

Dogs also enjoy specific spots like behind the ears, under the chin, the chest, and the belly, where petting is most pleasurable and calming. They often show enjoyment by relaxed body language, wagging their tail, and leaning into the touch.

In summary, dogs like to be petted because petting is pleasurable, emotionally reassuring, and strengthens the human-dog bond through physiological and social mechanisms.