<P> Born after an average of 63 days of gestation, puppies emerge in an amnion that 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 is necessary to ensure that the runts get proper nourishment and attention from the mother . As they reach one month of age, puppies are gradually weaned and begin to eat solid food . The mother may regurgitate partially digested food for the puppies or might let them eat some of her solid food . The mother dog usually refuses to nurse at this stage, though she might let them occasionally nurse for comfort . </P> <P> At first, puppies spend the large majority of their time sleeping and the rest feeding . They instinctively pile together into a heap, and become distressed if separated from physical contact with their littermates, by even a short distance . </P> <P> Puppies are born with a fully functional sense of smell but can't open their eyes . During their first two weeks, a puppy's senses all develop rapidly . During this stage the nose is the primary sense organ used by puppies to find their mother's teats, and to locate their littermates, if they become separated by a short distance . Puppies open their eyes about nine to eleven days following birth . At first, their retinas are 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 . Between two and four weeks old, puppies usually begin to growl, bite, wag their tails, and bark . </P> <P> 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 littermates, and begin to explore the world outside the nest . They play wrestling, chase, dominance, and tug - of - war games . </P>

When do new born puppies open there eyes