According to statistics published by the American Pet Products Manufacturers Association in the National Pet Owner Survey in 2009–2010, it is estimated there are 77.5 million people with pet dogs in the United States.[152] The same survey shows nearly 40% of American households own at least one dog, of which 67% own just one dog, 25% two dogs and nearly 9% more than two dogs. There does not seem to be any gender preference among dogs as pets, as the statistical data reveal an equal number of female and male dog pets. Yet, although several programs are ongoing to promote pet adoption, less than a fifth of the owned dogs come from a shelter.
Domestic dogs have been selectively bred for millennia for various behaviors, sensory capabilities, and physical attributes.[17] Modern dog breeds show more variation in size, appearance, and behavior than any other domestic animal.[17] Dogs are predators and scavengers, and like many other predatory mammals, the dog has powerful muscles, fused wrist bones, a cardiovascular system that supports both sprinting and endurance, and teeth for catching and tearing.
Wolves, and their dog descendants, likely derived significant benefits from living in human camps – more safety, more reliable food, lesser caloric needs, and more chance to breed.[135] They would have benefited from humans' upright gait that gives them larger range over which to see potential predators and prey, as well as better color vision that, at least by day, gives humans better visual discrimination.[135] Camp dogs would also have benefited from human tool use, as in bringing down larger prey and controlling fire for a range of purposes.[135]
Neutering reduces problems caused by hypersexuality, especially in male dogs.[76] Spayed female dogs are less likely to develop some forms of cancer, affecting mammary glands, ovaries, and other reproductive organs.[77] However, neutering increases the risk of urinary incontinence in female dogs,[78] and prostate cancer in males,[79] as well as osteosarcoma, hemangiosarcoma, cruciate ligament rupture, obesity, and diabetes mellitus in either sex.[80]
Cultural depictions of dogs in art extend back thousands of years to when dogs were portrayed on the walls of caves. Representations of dogs became more elaborate as individual breeds evolved and the relationships between human and canine developed. Hunting scenes were popular in the Middle Ages and the Renaissance. Dogs were depicted to symbolize guidance, protection, loyalty, fidelity, faithfulness, watchfulness, and love.[219]

Human emigrants from Siberia that came across the Bering land bridge into North America likely had dogs in their company. Although one writer[139] even suggests that the use of sled dogs may have been critical to the success of the waves that entered North America roughly 12,000 years ago,[139] the earliest archaeological evidence of dog-like canids in North America dates from about 9,400 years ago.[132]:104[140] Dogs were an important part of life for the Athabascan population in North America, and were their only domesticated animal. Dogs as pack animals may have contributed migration of the Apache and Navajo tribes 1,400 years ago. This use of dogs in these cultures often persisted after the introduction of the horse to North America.[141]
We continually review and update our pet grooming policies, procedures and standards, under the supervision of our Director of Veterinary Medicine, with counsel from a number of independent experts in animal care, behavior and ethics. We continue to train our teams on and reinforce the critical importance of following those policies at all times. Since 2015, we've worked together with the Pet Industry Joint Advisory Council (PIJAC) and the Professional Pet Groomers & Stylists Alliance (PPGSA) to encourage and support national health and safety standards for the grooming industry. We believe these standards are critical to the wellbeing of pets everywhere, and we continue to work with other pet industry leaders to encourage industry-wide adoption and adherence to them.