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]
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.
^ Lindblad-Toh, K.; Wade, C.M.; Mikkelsen, T.S.; Karlsson, E.K.; Jaffe, D.B.; Kamal, M.; Clamp, M.; Chang, J.L.; Kulbokas, E.J.; Zody, M.C.; Mauceli, E.; Xie, X.; Breen, M.; Wayne, R.K.; Ostrander, E.A.; Ponting, C.P.; Galibert, F.; Smith, D.R.; Dejong, P.J.; Kirkness, E.; Alvarez, P.; Biagi, T.; Brockman, W.; Butler, J.; Chin, C.W.; Cook, A.; Cuff, J.; Daly, M.J.; Decaprio, D.; et al. (2005). "Genome sequence, comparative analysis and haplotype structure of the domestic dog". Nature. 438 (7069): 803–819. Bibcode:2005Natur.438..803L. doi:10.1038/nature04338. PMID 16341006.
^ Fan, Zhenxin; Silva, Pedro; Gronau, Ilan; Wang, Shuoguo; Armero, Aitor Serres; Schweizer, Rena M.; Ramirez, Oscar; Pollinger, John; Galaverni, Marco; Ortega Del-Vecchyo, Diego; Du, Lianming; Zhang, Wenping; Zhang, Zhihe; Xing, Jinchuan; Vilà, Carles; Marques-Bonet, Tomas; Godinho, Raquel; Yue, Bisong; Wayne, Robert K. (2016). "Worldwide patterns of genomic variation and admixture in gray wolves". Genome Research. 26 (2): 163–173. doi:10.1101/gr.197517.115. PMC 4728369. PMID 26680994.
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.