The reason why dogs do not have clavicle is due to physiological reasons. Because the nature of dogs is to hunt, the lack of clavicle helps dogs run and jump, and allows the muscles of the front legs to stretch and contract more flexibly. Therefore, dogs do not have clavicle. The bones in the forelimb bones are directly connected, called muscle groups in the forelimb area, but this also causes the dog to be unable to complete some actions, and basically bites with its mouth when fighting.