Puppies of different breeds are born with different size and weight but all of them are born blind and deaf. Average weight of newborn cubs is 450 grams. The average litter consists of 5 pups. Litters of 12 pups are born rarely.

In the early days of his life puppy sleeps 90% of the time, and the remaining 10% — eat. Thus most of the time babies sleep.

On 13 day pups open their eyes. Of course, even here there are exceptions. In this period in a litter of 10 Foxteriers 9 out of 10 will be sighted, but in a litter of 10 beagles, only 1 in 10 will see. By 21 days of their lives puppies of all breeds have their eyes opened. At this time puppies are already can hear and they show «the first signs of activities.»

3-week-old puppies are also beginning to wave their tails and try to bark. In this age they also crawl away from the nest to relieve themselves.

4-week-old puppies increase their weight seven more till the time of their birth. At this time begins the primary socialization of puppies. They play with each other and learn the typical behavior for their species.

At the age of 5 weeks the puppies are developing facial muscles. So their communication become more complecated.

At 6 weeks, puppies begin to establish a hierarchy between them.

After 7 weeks bitch completely ceases to feed the puppies and they can go to new homes. At this age it is easiest to adapt to their new families. But for some breeds more optional age for leaving kennel is 10 weeks of age.

When the puppies are 12 weeks old they are passed through second period of socialization. Wild puppies at this time take an active part in the life of the pack as well as in a joint hunt.

At the age of 16 weeks begins the process of changing teeth which ends in 24 months.

6-month-old males are starting to perk up during walks and reach sexual maturity. Full sexual maturity in both sexes ends to 9 months, although there are exceptions in some breeds that reach it by 12 months.