A puppy is a juvenile dog, generally less than one year of age. The term is sometimes abbreviated to pup, and in that form is used for the young of some other animals, such as the wolf.
Birth and Development
The number of puppies in a litter varies greatly by breed. Some smaller dogs bear only one or two puppies at a time, while some larger breeds bear a dozen or more. In some cases, one puppy will be the runt of the litter, being noticeably smaller than the others. The runt is generally quite meek or very aggressive because of its size compared to its siblings.
Born after approximately 63 days of gestation, puppies emerge in an amnion which is bitten off and eaten by the mother dog.
Puppies begin to nurse almost immediately. If the litter exceeds six puppies, particularly if one or more are obvious runts, human intervention in hand-feeding the stronger puppies will be necessary to ensure that the runts get proper nourishment and attention from the mother to thrive. As they reach one month of age, the puppies are gradually weaned and begin to eat solid food. The mother may regurgitate partially digested food for the puppies to eat or might let them eat some of her solid food. By the age of about seven weeks, puppies no longer depend on nursing for food. Although they may continue trying to nurse, the mother dog may no longer allow them to after this age; still, she might let them occasionally nurse for comfort.
At first, puppies spend ninety percent of their time sleeping and the rest feeding. During their first two weeks, although it is not completely visible, a puppy's senses all develop rapidly. Puppies open their eyes about nine to eleven days following birth. At first, the retina is poorly developed and their vision is poor. Puppies are not able to see as well as adult dogs. In addition, puppies ears remain sealed until about thirteen to seventeen days after birth, after which they respond more actively to sounds. From two to four weeks, puppies usually begin to growl, wag their tails, and bark.
Puppies develop very quickly during their first three months, particularly after their eyes and ears open and they are no longer completely dependent on their mother. Their coordination and strength improve, they spar with their litter-mates, and begin to explore the world outside the nest. They play wrestling, chase, dominance, and tug-of-war games.
Puppies are highly social animals and spend most of their waking hours interacting with either their mother or littermates. Most experts now believe that being with its mother and littermates until at least eight weeks is important for a puppy's behavioral development. Responsible breeders will not sell a puppy that is younger than eight to twelve weeks, and in many jurisdictions, it is illegal to give away puppies younger than a certain age (usually between eight and twelve weeks).
It is important that the puppy receive regular positive socialisation with other dogs and humans during the first sensitive period (eight to twelve weeks). Puppies should be exposed to as wide a variety of friendly people and dogs as possible during this period. Dogs that do not receive adequate socialisation during the first sensitive period may display fearful behaviour around humans or dog as adults. Males tend to be more hyper active when they are young.
Cropping and Docking
Some breeds traditionally have their tails docked or ears cropped, or both. Many countries now ban cropping and docking for cosmetic purposes, but other countries have no such prohibitions. Some breeders prefer to remove a dog's dewclaws to prevent future injuries. All of these procedures are usually performed within the first few days at the veterinarian's office.
Puppies can be touched and held from birth, although only briefly and occasionally until their eyes and ears open. After that, it is critical for their socialization that they interact often with humans.
Puppies can begin learning what a leash feels like as soon as they are old enough to begin exploring outside their whelping box, just by attaching a leash to their collar and letting them pull it behind them, then walking with the puppy around the house or yard holding onto one end of the leash.
Training of basic obedience can begin at the same time, although recommendations for how intense and how soon vary. Training for young puppies is generally recommended to be light, gentle, and fun, more like a game than an exercise. Most formal puppy classes accept puppies starting at three months of age, although some provide socialization classes for younger pups.
Housebreaking can also begin by the time the puppy is two to three months old, although they simply do not have the physical control of their bodies to be completely reliable until they are six months to a year old.
Perceptions of Cuteness
Puppies are stereotypically (and typically) very cute to human perception. Many puppies are brought home as pets, after which the owner discovers that they can be destructive and time consuming to train, and might grow into much larger dogs than expected. Experts recommend that potential owners of puppies investigate what is involved in raising a puppy and what its parents look like before making a decision to purchase or adopt a puppy.