Wolves and Dogs Use Showing Behavior to Indicate Location of Out-of-Reach Food
JoAnna Pendergrass, DVM
Dr. Pendergrass received her DVM degree from the Virginia-Maryland College of Veterinary Medicine. Following veterinary school, she completed a postdoctoral fellowship at Emory Universitys Yerkes National Primate Research Center. Dr. Pendergrass is the founder and owner ofJPen Communications, a medical communications company.
A recent study reported that captive wolves and dogs, when raised under identical conditions, use showing behavior to indicate the location of out-of-reach food to cooperative humans.
In a recent study published in Animal Behaviour, captive wolves and dogs raised under identical conditions at the Wolf Science Center (WSC) in Ernstbrunn, Austria displayed "showing behavior" to indicate the location of out-of-reach food to cooperative humans.
Humans and animals have various ways of communicating when they want an out-of-reach object. For example, children will use imperative pointing to let an adult know when they want something. Likewise, captive chimpanzees, when interacting with humans, have used imperative pointing to indicate out-of-reach food or objects.
Animals without hands use gaze alteration, along with other behaviors, to indicate an inaccessible object. For example, dogs alternate their gaze between an inaccessible object and a human. Wolves have also demonstrated gaze alteration when communicating with humans, but less so than dogs; this suggests the influence of domestication on this type of communication with humans.
In this recent study, the authors included a definition of "showing behavior" from a previous study: “a communicative behaviour consisting of a directional component referring to an external target and an attention-getting component that attracts the receiver's attention to the sender.”
Thirteen adult dogs (7 males, 6 females) and 8 adult timber wolves (5 males, 3 females), aged 1.5 to 3.5 years, were used in the study. All of the subjects were captive-born, weaned from their mothers by 10 days of age, and identically hand-raised and socialized at the WSC. Each subject had received daily obedience training and regular cognitive behavioral testing since puppyhood.
In the experiment room, the authors hung three boxes high enough to be inaccessible to the subjects. Three people familiar to the subjects participated in the study. One person was the experimenter, who hid a piece of sausage in one of the three boxes. The other two people were either the “cooperative” partner (rewarded subjects with the hidden food) or “competitive” partner (ate the hidden food).
Prior to testing, the subjects learned that food was hidden in the boxes and that a human could give them this food (“prefeeding” phase). During training and a subsequent preference test, the subjects learned the difference between the cooperative and competitive partners.
During testing, which occurred over two days, the experimenter showed the subject a piece of sausage and hid it in one of three boxes. Next, one of the two partners entered the room, watched the subject closely for one minute, then walked to the box indicated by the subject. If food was in the box, the partner either rewarded the subject or ate the food. If the box was empty, the partner showed the subject the empty box and left the room. Each subject was tested twice by each type of partner.
Video recordings of the experiment were analyzed for showing behavior, such as how often a subject displayed gaze alteration between the boxes and the human partner, and how often it contacted the human partner.
Both species were significantly more likely to show the food location to the cooperative partner than the competitive partner, indicating each species’ ability to modify their showing behavior based on the cooperativeness of the human partner.
The frequency of looking at any of the potential food locations was significantly greater with wolves than dogs, potentially signifying a higher food motivation in wolves than dogs.
Regardless of which human partner was present, both species looked at any of the food locations more frequently on day 1 than on day 2 of testing, suggesting that the subjects’ motivation by the test’s novelty was higher on the first day of testing.
Regarding contact with the human partner, the frequency and duration of looking at the human partner’s face were significantly greater with the dogs than with the wolves. In addition, dogs went to the human partner more frequently than the wolves did.
Differences were also observed when evaluating the type of human partner and duration of human contact. Wolves and dogs spent approximately equal amounts of time in contact with the cooperative partner. However, when the competitive partner was present, dogs spent more time with them than the wolves did.
The authors suggested that, because of a dog’s higher dependence on humans, the study’s dogs looked at the human partners more often and were less discriminating when spending time with the different partners.
In addition, the authors noted that the study’s subjects used showing behaviors “less often than pet dogs living with human families, suggesting that closeness to humans and different experiences with them can strongly influence the showing behaviour of dogs.”
Dr. JoAnna Pendergrass received her doctorate in veterinary medicine from the Virginia-Maryland College of Veterinary Medicine. Following veterinary school, she completed a postdoctoral fellowship at Emory University’s Yerkes National Primate Research Center. Dr. Pendergrass is the founder and owner of JPen Communications, LLC.