Age-graded dominance hierarchies and social tolerance in packs of free-ranging dogs

It is believed that domestic dogs rarely form packs with age-graded hierarchical structures similar to those found in wolves. Dog-wolf comparisons in captivity suggest that human control has reduced dog dependency on cooperation with conspecifics, resulting in a more despotic dominance order. However, free-ranging dogs are under stronger natural selection than purebred dogs. They are dependent on companions’ social support but usually exhibit lower reproductive skew than wolves, possibly because access to easily available human-derived food may have relaxed within-group competition. We investigated social dominance in 5 packs of mongrel dogs living in a free-ranging or semifree-ranging state. We aimed at replicating the findings of the few studies that detected a dominance hierarchy in dogs using a larger sample of packs. Additionally, we provided behavioral measures of social tolerance. We found that a linear hierarchy existed in all packs studied and that the rank order was positively...