In general, a dog ages must quicker than a human does. Some believe that every dog year equals seven human years. But this isn’t always true since a dog’s age in human years can be affected by his breeding and his size. If you want to know how old your dog really is, just ask your veterinary clinic Columbia, MD  staff for help. In most cases, a small dog will have a longer life span than a large dog. Why is this? Some research suggests that larger dogs start to age at an earlier point in life. There are some veterinarians that have noted a larger dog’s cell growth seems to be much more accelerated than a small dog’s. If a larger dog becomes sick or develops a disease, he is much more likely to die at an earlier age because of the rapid growth of the illness. Smaller dogs tend to develop at a slower pace.