The social behaviour of free-ranging suburban dogs

Abstract

Over a period of 7 months, a residential area of Berkeley, California, was surveyed at hourly intervals throughout the day and night for free-ranging dogs, dogs with people, and cats. The animals' locations and behaviours were recorded. The highest frequency of sightings of free-ranging dogs occurred at 07.00 h, with a secondary peak at 17.00 h. The abundance of dogs with people followed a similar pattern except that the morning peak occurred 2 h later. Cats were most abundant at night between 18.00 and 04.00 h. The observable number of free-ranging dogs increased with increasing temperature to a maximum at 23° C and then declined with higher temperatures. The number of cat sightings was fairly constant with increasing temperature up to 17° C then declined with further temperature increase. Free-ranging dogs were sighted most frequently on private property. Street and side-walk use was greatest in the mornings; free-ranging dogs tended to travel in the morning and rest as the temperature increased later in the day. Most dogs were sighted within 1 or 2 blocks of their homes. The home ranges of 8 dogs are illustrated and described. These showed considerable individual variation, but generally had dense core areas and sparse travel areas (mean corridor home range = 1.74 hectares). Most free-ranging dogs were solitary and social groupings occurred only randomly. Despite their apparent lack of sociability, the dogs did not exhibit any signs of territoriality and agonistic encounters were never observed.