The social organization of free-ranging urban dogs. II. estrous groups and the mating system

The breeding behavior of free-ranging dogs (Canis familiaris) was studied in Newark New Jersey, in the summer of 1978 and the winter of 1978–1979. The presence of an estrous female in an area led to increased aggression and hierarchy formation among males as they congregated around the female and attempted to mate. Data on estrous group dynamics, as well as evidence for female mate-selection, were gathered.

Males were categorized as either familiar or unfamiliar to the female, based on the proximity of their home-range core areas. Familiarity appeared to be a critical factor in mating success, as unfamiliar males were never observed mating; they generally remained in the estrous group for shorter periods of time and suffered a disproportionate number of attacks in comparison to familiar males.

While the consequences of such mate-selection are not clear, it is suggested that the observed behavior may be a vestige from a monogamous ancestor in which long-term pair bonds and paternal care predispose the female to choose males about whom she has more information. A shift to promiscuity in domestic dogs should not imply indiscriminate mating.