Depending on the breed, dogs can live an average of 10 to 15 years or more and with an improved understanding of veterinary medicine, dogs are living healthier and longer lives. Like humans, as dogs progress from youth to later years, they go through physical and emotional changes. Each stage has its own uniqueness and importance and the ability to recognize and accept these changes makes the human-dog bond even more special.

Puppy

Newborn puppies sleep almost constantly for the first week or two of their lives. Born blind and deaf, a 2-day-old Labrador retriever puppy is still capable of feeling, smelling and tasting. By 2 or 3 weeks of age, it will start seeing and hearing, while its other senses continue to develop. And by the end of the first month, it will begin to growl, howl and bark.

Between 4 and 6 weeks of age, both domestic and wild pups, like rambunctious young coyotes, are strong and coordinated enough to engage in some rough-and-tumble play-fighting with their littermates. By 10 to 12 weeks of age, fully weaned and strengthened by solid food, wild canid pups start wandering farther and farther from their dens.

Marked by the onset of puberty and its raging hormones, most canids enter the turbulent period of adolescence at about 6 months of age. Flooded by an onslaught of testosterone, male dogs in particular begin discovering their own sexuality. They may have undergone some emotional and sexual changes early in life, but won’t reach true sexual maturity until much later. A release of sex hormones just before birth is said to “masculinize” the male dog’s brain; his testes descend into the scrotum before he is a month old. And even though they may display mounting and other sexual behaviors at a very young age, males — like females — only become sexually mature and capable of reproducing after they have reached puberty. Their newfound sexual drive will likely inspire frequent roaming, aggression toward other males and urine marking as they begin seeking out available females for mating.