Small or medium-size dogs usually live to be around 15 years of age, and large dogs live to be about ten years old. A fertile dog can produce about two litters a year with an average of six to ten puppies. Puppies grow in their mother's womb until they are born, also known as whelped. Dogs drink milk from their mother until they are weaned, and then they graduate to eating solid foods. Weaning can happen as early as week three, but pups should not be weaned any time after the seventh week.

Pups get baby teeth, often called milk teeth, that are mostly incisors and canines sometime between week three and week six. By month three, the first of the permanent teeth come in by the third month and the puppy should have all its teeth by month seven.

A ten-month-old dog is sexually mature. Smaller female dogs go into their first heat and can mate at a younger age than big dogs. Dogs are sexually mature beforehand; a dog ordinarily does not attain full growth until it's one year old, and sometimes even later. A puppy becomes a mature dog by the time it is one year old. Female dogs usually go into heat about every six months and will mate within the three-week time period the heat.

When a dog meets another dog, its ear position will indicate whether or not it is interested in the other dog. If a dog's ears are erect it means that it's probably focused on the other dog and happy, but if the ears point forward, it means that the dog is on alert. If a dog wags its tail, holding it high, this means that the dog is happy and confident. If a dog drops its tail and it remains still, it means the dog is apprehensive. If the dog puts its tail between the legs then that means that the dog is afraid.

If a dog growls or pulls its lips back to expose teeth when meeting someone, even another dog, it is making a threat. If it bares teeth with no growling then the dog may be ready to bite or attack. Male dogs establish territories by marking areas with urine and a scent that comes from their anal glands. A dog will defend its territory against intruders.

When a dog gets old, the first sign is that the eyes begin to weaken whereby they cloud and cataracts may form in the eye's lenses. Its hair begins to slowly turn gray, and it's evident that older dogs are suffering from various aches and pains. Uncomfortable older dogs might become agitated and even snap at members of the family. As the dog's systems break down with old age, it is readying itself for death.

When a dog has had a stroke, its kidneys fail and it stops eating, or other dogs around it begin to snap and push it away. It may mean the time has come for death and if the dog is suffering a veterinarian will know if it should be put to sleep.

Pets are an integral part of our lives today so losing them can be very painful. The death of a pet can be very difficult, but there are ways that a dog's life can be honored.

There are special websites for virtual online pet memorial products such as cremation pet urns and grave markers so that people have the opportunity to honor their pets, which helps us through our grieving just a little bit more.