The great multitude of different breeds of dog and the countless differences in their size, points, and all around appearance are facts which make it hard to believe that they could have a common ancestry. For example, when considering the behavioral and physical differences between such breeds as the pampered Min Pin and the hard-working Husky, the disparity is so great, yet they are the same species. If the two were to somehow mate, viable offspring would be born. Yet the disparity is no greater than that between the Shire horse and the Shetland pony, the Shorthorn and the Kerry cattle, or the Patagonian and the Pygmy; and all dog breeders know the simple steps needed to produce a variety in type and size by breeding.
Before one can fully understand that dogs and their wild counterparts share a close ancestry, one must start by learning the basic physical similarities between them. The skeletal system of the two animals is an ideal place to begin study since they are virtually interchangeable. The spine of the dog consists of seven vertebrae in the neck, thirteen in the back, seven in the loins, three sacral vertebrae, and twenty to twenty-two in the tail. In both the dog and the wolf there are thirteen pairs of ribs, nine true and four false. Each has forty-two teeth. They each have five front and four hind toes, and a quick look at the outward appearance shows that describing a wolf is the same as describing a large dog.
Their habits are not that different, either. In the wild, wolves are known to howl in their packs, but as soon as a wolf is grouped with dogs, he takes on barking behavior. Although he is carnivorous, he will also eat vegetables, and when sickly he will nibble grass. In the chase, a pack of wolves will divide into parties, one following the path of the quarry, the other endeavoring to intercept its retreat, exercising a great amount of cooperation, a trait which is exhibited by many of our sporting dogs and terriers when hunting in teams.
Another major similarity between these two species is the sixty-three day gestation period. Usually, a wolf?s litter consists of about three to nine cubs, and they are unable to see for twenty-one days. They are nursed for two months, but at the end of that time they are able to eat half-digested flesh disgorged for them by their dam or even their sire.
