Answers: 1.Circulatory system-pumping blood to and from the body and lungs with the heart 2.Digestive system-digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, rectum, and anus.
During the tie, the male turns around so the dogs are back to back and can defend themselves. The tie typically lasts 20 to 40 minutes. It may be just a few minutes, and dogs can mate successfully without becoming tied at all. The evolutionary reason for the tie is unknown, but it's assumed that if a male dog is tied to a female, it prevents other males mating with her. Unwanted Mating.
However if there is an adult (19 years or older) outside with the dog, he can be tied up as long as the adult is with him. The dog also needs to be on a long enough tie-out that he can move freely (5 times his body length) and weighs just 1/8 of his bodyweight (no big tow chains).