One of the first domesticated animals was a dog. The first tamed dogs were used by man exclusively for their exploitation on the farm: on the hunt, for protection, as sled dogs.

Examining the remains of the ancestors of domestic dogs, scientists concluded that their spine underwent structural changes. If we talk about other animals, for example, wolves, such deformations are much less common in them. The reason for this skeletal deformation was the rapid aging of cartilage and bones as a result of increased load on the skeleton, as well as rapid aging. With the growth of bone tissue, the flexibility of the ligaments between the spines decreases by several orders of magnitude. For the health of dogs, such deformation does not pose a particular danger, but, nevertheless, it creates some inconvenience.

Scientists Robert Lozi and Catherine Latham of the University of Canada refute the hypothesis that the main reason for the skeleton deformation of dogs is the dragging of heavy loads. They reported this in their article in Plos One magazine.

They are sure that skeletal deformity (spondylosis) is equally common in dogs and wolves. Sled dogs suffer from this ailment much more often. This is especially noticeable in dogs whose age is more than 8 years. The authors of the article argue that the main reason for spondylosis lies in the domestication of dogs.In ancient dogs, the disease is due to the fact that they lived in close proximity to the person who took care of them.

The first domesticated dogs lived much longer than wild dogs. This contributed to the emergence of a long period of time for the development of spondylosis.

Each of these two hypotheses has a right to life. The truth will be established in the process of analyzing the remains of ancient dogs, as well as modern animals.