At least 33,000 years ago, humans began the process of domesticating certain members of the gray wolf species. Since that process began, humans have genetically manipulated canines to fill various roles – beginning with tasks that increased means of survival and later to simply serve as companions. Those evolutionary changes have been a benefit to humans, but have caused health issues within many dogs – because as we’ve bred for desired physical traits, detrimental genetic mutations have also been passed along within many breeds.
The consistent selective breeding of canines has led to hundreds of breeds with standard and predictable attributes, or traits.
For example, the short-legged, long-bodied dachshunds allowed them to easily enter underground tunnels and burrows of badgers and other small animals; long-eared, keen-smelling bloodhounds were bred to trail deer, wild boar and later humans; some of the oldest breeds, the sight hounds, which include greyhounds, whippets and saluki, were selectively bred for long legs, strong aerobic endurance, sharp eyesight and the desire to chase feathered and furred game.
These consistent traits were brought about by mixing several different canines that possessed desired attributes (i.e., flat-coated retrievers were likely a combination of St. John’s Water Dogs ...