Domestic dogs inherited complex behaviors, such as bite inhibition, from their wolf ancestors, which would have been pack hunters with complex body language. These sophisticated forms of social cognition and communication may account for their trainability, playfulness, and ability to fit into human households and social situations, and these attributes have given dogs a relationship with humans that has enabled them to become one of the most successful species on the planet today.:pages95-136
Although dogs are the most abundant and widely distributed terrestrial carnivores, the potential of feral and free-ranging dogs to compete with other large carnivores is limited by their strong association with humans. For example, a review of the studies in the competitive effects of dogs on sympatric carnivores did not mention any research on competition between dogs and wolves. Although wolves are known to kill dogs, they tend to live in pairs or in small packs in areas where they are highly persecuted, giving them a disadvantage facing large dog groups.
In Christianity, dogs represent faithfulness. Within the Roman Catholic denomination specifically, the iconography of Saint Dominic includes a dog, after the hallow's mother dreamt of a dog springing from her womb and becoming pregnant shortly thereafter. As such, the Dominican Order (Ecclesiastical Latin: Dominicanus) means "dogs of the Lord" or "hounds of the Lord" (Ecclesiastical Latin: domini canis). In Christian folklore, a church grim often takes the form of a black dog to guard Christian churches and their churchyards from sacrilege.
In 1999, a study of mitochondrial DNA indicated that the domestic dog may have originated from multiple grey wolf populations, with the dingo and New Guinea singing dog "breeds" having developed at a time when human populations were more isolated from each other. In the third edition of Mammal Species of the World published in 2005, the mammalogist W. Christopher Wozencraft listed under the wolf Canis lupus its wild subspecies, and proposed two additional subspecies: "familiaris Linneaus, 1758 [domestic dog]" and "dingo Meyer, 1793 [domestic dog]". Wozencraft included hallstromi – the New Guinea singing dog – as a taxonomic synonym for the dingo. Wozencraft referred to the mDNA study as one of the guides in forming his decision. The inclusion of familiaris and dingo under a "domestic dog" clade has been noted by other mammalogists. This classification by Wozencraft is debated among zoologists.
Amongst apprenticeship programs and other hands-on training activities, Petco pet stylists who are trained from within the company are required to attend and pass Petco's comprehensive 12-week Pet Stylist Apprentice & Certification academy program. In addition to hands-on grooming training with a Petco-certified pet stylist mentor or instructor, all participants receive instruction in health, safety protocols and grooming salon operations. At the end of the program, candidates must pass a technical skills assessment in order to become a Petco Certified Pet Stylist.