Puppy

A puppy is a juvenile dog. Most puppies are considered puppies until they are between 12 and 18 months old. These young animals are born in a state called altriciality. This means they are markedly underdeveloped and depend entirely on their mothers for survival. While they start out very small, healthy puppies grow at a very rapid rate. Their physical appearance can even shift during this time. For example, the coat color of a Yorkshire Terrier may change as the dog matures.

Before birth, a puppy undergoes a complex prenatal development process. This process consists of three distinct phases: the germinal stage, the embryonic stage, and the fetal stage. The germinal stage begins at fertilization and lasts for approximately two weeks. During this time, a fertilized egg, known as a zygote, travels through the fallopian tube toward the uterus. The zygote undergoes rapid cell division while moving. Once the zygote reaches the uterus and settles into the uterine wall, the placenta forms. The placenta is a vital structure that will eventually feed the growing puppy.

The second phase is the embryonic period, which lasts from about day 14 to day 28 of pregnancy. During this stage, the embryo begins to take on a recognizable shape. This happens because important body systems and organs begin to grow. These include the brain, the heart, the lungs, and the digestive system. An embryo during this stage is quite small, roughly the size of a grape. Following this, the fetal period begins around day 28 and continues until birth around day 63. During this time, the puppy's organs and systems continue to refine and develop. The puppy also gains the ability to control its own body temperature. Additionally, its senses, such as sight and hearing, undergo maturation.

Most puppies are born after an average gestation period of 63 days. They emerge from an amnion, which the mother dog bites off and eats. Almost immediately after birth, puppies begin to nurse. If a litter has more than six puppies, humans may need to intervene. This is especially true if there are "runts," which are puppies that are smaller or weaker. In these cases, humans may hand-feed the stronger puppies to ensure the runts receive enough nourishment. By one month of age, puppies begin the process of weaning. This means they gradually start eating solid food. The mother might let them eat her food or may regurgitate partially digested food for them.

Early puppy life is defined by rapid sensory development. Although puppies are born with a functional sense of smell, they cannot open their eyes. They rely on their noses to find their mother's teats and to locate littermates. Their eyes typically open between nine and eleven days after birth. However, their vision is initially poor because their retinas are not fully developed. Their ears remain sealed until they are between thirteen and seventeen days old. Once the ears open, puppies respond more actively to sounds. By two to four weeks of age, puppies often begin to exhibit behaviors like barking, growling, biting, and wagging their tails.

As puppies reach three months of age, they become much more independent. Their coordination and physical strength improve significantly. They often engage in social play with their littermates, such as wrestling, chasing, or tug-of-war. This period is also critical for socialization. Socialization involves interacting with humans and different environments. The most important window for this is between eight and twelve weeks of age. The American Kennel Club suggests that puppies should meet "100 People by 12 Weeks." Proper socialization helps prevent fearful behavior in adult dogs.

Humans sometimes perform certain procedures on puppies, such as docking or declawing. Docking involves removing part of a dog's tail. Originally, this was done to prevent injuries in working dogs, but it is now often done for cosmetic reasons. Because of this, many countries, including Australia and most of Europe, have banned cosmetic docking. The United States still permits the practice, though the American Veterinary Medical Association opposes it. Similarly, some breeders use declawing to prevent scratches or to manage dewclaws. These procedures are usually performed by a veterinarian or an experienced breeder within the first few days of a puppy's life.