puppy

A puppy is a juvenile dog. Some puppies can weigh , while larger ones can weigh up to . All puppies display primary altriciality and healthy puppies grow quickly after birth. A puppy's coat color may change as the puppy grows older, as is commonly seen in breeds such as the Yorkshire Terrier. Puppy refers specifically to young dogs, while pup may be used for other animals such as wolves, seals, giraffes, guinea pigs, rats or sharks. Prenatal Development Dogs go through prenatal development before they are born, just like all animals do. The germinal stage, the embryonic stage, and the fetal stage are the three phases that make up this development. The first stage of prenatal growth in dogs is known as the germinal stage, which starts at fertilization and lasts for about two weeks. The fertilized egg, also known as the zygote, travels through the fallopian tube to the uterus during this period while undergoing rapid cell division. The placenta, which will feed the growing puppy, is formed once the zygote enters the uterus and settles in the uterine wall. The embryonic period lasts from about day 14 of pregnancy until day 28 or so. With the growth of important organs and body systems, the embryo starts to take on a more recognizable shape at this stage. This involves the development of the digestive system, brain, heart, and lungs. An ultrasound can show the embryo at this time, which is about the size of a grape.