BEHAVIORAL AND GLUCOCORTICOID RESPONSES OF ADULT DOMESTIC DOGS (CANIS-FAMILIARIS) TO COMPANIONSHIP AND SOCIAL SEPARATION

Removal of 1 member of a long-standing pair of adult domestic dog (Can is familiaris) kennel mates from the home run for 4 hr had no effect o n the behavior or plasma glucocorticoid levels of the remaining dog. W hen tested in a novel environment, dogs showed increased activity and elevated glucocorticoid levels at the end of the session, but these re sponses were as large when the dogs were with their kennel mates as wh en they were alone. However, activity and glucocorticoid levels were n ot elevated if the dogs were exposed to the novel environment in the p resence of their human caretaker. Dogs more often were observed in pro ximity with, and soliciting social behavior from, the human than the k ennel mate. These results highlight the importance of human companions hip for the domestic dog and point to a difference in the nature of th e social relationships of dogs with humans and with conspecifics.