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.
At this point, your puppy can only hold his bladder for around 2 hours. It is also the best time to start housebreaking. At 16 weeks, a puppy can usually hold his bladder for up to four hours. Prior to this, the bladder can withstand about 2 hours before the puppy must go. At 4-6 months, puppies in this age group can often seem half house trained due to their ability to be easily distracted.