It is a reflexive action for many dogs to try to pull away their back leg if it is lifted. Avoid lifting the leg to the side because this is uncomfortable for most dogs. Instead, pick up the foot and gently pull forward or backward. Don't be upset or punish the dog, just struggle through it and praise your dog when he or she is still. If you have a medium or large dog, you may be able to get away with clipping the nails on the hind feet without having to lift the foot.
The genetic divergence between dogs and wolves occurred between 40,000–20,000 years ago, just before or during the Last Glacial Maximum.[27][2] This timespan represents the upper time-limit for the commencement of domestication because it is the time of divergence and not the time of domestication, which occurred later.[27][28] The domestication of animals commenced over 15,000 years ago, beginning with the grey wolf (Canis lupus) by nomadic hunter-gatherers.[27] The archaeological record and genetic analysis show the remains of the Bonn–Oberkassel dog buried beside humans 14,200 years ago to be the first undisputed dog, with disputed remains occurring 36,000 years ago.[2] It was not until 11,000 years ago that people living in the Near East entered into relationships with wild populations of aurochs, boar, sheep, and goats.[27]
Unlike other domestic species which were primarily selected for production-related traits, dogs were initially selected for their behaviors.[96][97] In 2016, a study found that there were only 11 fixed genes that showed variation between wolves and dogs. These gene variations were unlikely to have been the result of natural evolution, and indicate selection on both morphology and behavior during dog domestication. These genes have been shown to affect the catecholamine synthesis pathway, with the majority of the genes affecting the fight-or-flight response[97][98] (i.e. selection for tameness), and emotional processing.[97] Dogs generally show reduced fear and aggression compared with wolves.[97][99] Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and then later in breed formation.[97] Traits of high sociability and lack of fear in dogs may include genetic modifications related to Williams-Beuren syndrome in humans, which cause hypersociability at the expense of problem solving ability.[100][101][102]
The practice of using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders.[201] Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase social behaviors, such as smiling and laughing, among people with Alzheimer's disease.[202] One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives, and decreased antisocial and violent behavior compared with those who were not in an animal-assisted program.[203]
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]
Certain Pacific islands whose maritime settlers did not bring dogs, or where dogs died out after original settlement, notably: the Mariana Islands,[123] Palau,[124] Marshall Islands,[125] Gilbert Islands,[125] New Caledonia,[126] Vanuatu,[126][127] Tonga,[127] Marquesas,[127] Mangaia in the Cook Islands, Rapa Iti in French Polynesia, Easter Island,[127] Chatham Islands,[128] and Pitcairn Island (settled by the Bounty mutineers, who killed off their dogs in order to escape discovery by passing ships[129]).
Citing a 2008 study, the U.S. Center for Disease Control estimated in 2015 that 4.5 million people in the USA are bitten by dogs each year.[176] A 2015 study estimated that 1.8% of the U.S. population is bitten each year.[177] In the 1980s and 1990s the US averaged 17 fatalities per year, while since 2007 this has increased to an average of 31.[178] 77% of dog bites are from the pet of family or friends, and 50% of attacks occur on the property of the dog's legal owner.[178]
The domestic dog (Canis lupus familiaris when considered a subspecies of the wolf or Canis familiaris when considered a distinct species)[5] is a member of the genus Canis (canines), which forms part of the wolf-like canids,[6] and is the most widely abundant terrestrial carnivore.[7][8][9][10][11] The dog and the extant gray wolf are sister taxa[12][13][14] as modern wolves are not closely related to the wolves that were first domesticated,[13][14] which implies that the direct ancestor of the dog is extinct.[15] The dog was the first species to be domesticated[14][16] and has been selectively bred over millennia for various behaviors, sensory capabilities, and physical attributes.[17]
Experienced pet stylists hired from outside the company must complete a personal skill evaluation by a Petco Certified Pet Stylist or Grooming Salon Leader, as well as four weeks of safety and pet grooming operations training. They must also complete and pass a technical skills assessment within 14 days of hire. If the candidate does not pass the technical evaluations, they must complete Petco's 12-week Pet Stylist Apprentice & Certification program and retake the skills assessment.