Our domestic dogs are not wolves, and some interesting evidence about the difference between dogs and wolves comes from the way that they form attachments with other living beings. It may well be the case that we have selectively bred dogs to love humans more than they love animals of their own species. I use the word "love" even though psychologists and behavioral biologists tend to shy away from the word, and prefer terms like "attachment" or "bonding". Many scientists have the feeling that the word "love" is reserved for poets and songwriters, rather than hard-nosed researchers. Furthermore, a number of researchers who accept love as a valid feeling to reference to humans, still have doubts as to whether dogs can actually experience that same emotion.
As is often the case, we are often led to wrong conclusions about the nature of dog behavior based upon observations of captive wolves. Over the past half century it has become common place to assume that since dogs were likely domesticated from wolves that we get a clearer and undistorted look at the natural behavioral predispositions of dogs by looking at what wolves do. Thus it is well known that wolves that are isolated from other members of their pack become anxious. If they are in unfamiliar settings they seem to draw comfort from having members of their pack around them. Furthermore, wolves seldom form close attachments to their human captors. From this people have assumed that dogs naturally bond with other canines, and their attachment to people is secondary.
I recently rediscovered a research report that had been published in the Journal of Comparative Psychology by a research team headed by Michael Hennessey of Wright State University, along with some scientists from Ohio State University (David Tuber, Suzanne Sanders and Julia Miller). This study shows just how domesticated our pet dogs have become and how their orientation seems to have shifted more towards humans than to other dogs.
The animals involved in this research were eight mixed breed dogs who were 7 to 9 years of age. They had been living as littermate pairs in kennels since they were eight weeks old. All these dogs had been fully socialized when they were young and were quite comfortable around people. They were being looked after by one caretaker who, at least as far as the dogs were concerned, was their owner. The important factor for us is that when the experiment began these kennel mates had not been separated from each other (even for a few minutes) over the previous two years, and had seldom been apart during their entire lifetimes.
To test their attachment to each other, one member of each pair was removed from the kennel for four hours and the remaining animal was observed. If you take a puppy away from its litter mates it will usually whimper and act distressed until it is reunited with its litter mates, however these adult dogs, when left alone in their kennel, did not show any evidence of anxiety. They rarely barked or paced, and the level of thestress hormone, cortisol, in their blood didn't change as a result of their separation from their kennel mate. This was true as long as the remaining dog was left in its familiar pen.
The situation was quite different when the dogs were placed alone in an unfamiliar kennel. Now they clearly showed signs of unease and apprehension. They became agitated and their stress hormone level went up by more than 50 percent. The most important finding is that this increase in anxiety happened whether the dog was alone or if it had been moved to the unfamiliar place in the company of its kennel mate. In this unfamiliar place the dogs did not interact very much, and did not seem to draw comfort from the presence of their usual partner as shown by the level of stress hormone in their blood.
The situation was quite different, however, when their human caretaker sat quietly with each dog in this new and strange situation. Under these circumstances the dog would stay close to the human and would try to get him to interact and make contact. In response to this comfort-seeking behavior, the caretaker would briefly stroke the dog. This interaction with a human seemed to be enough to reduce the dogs level of anxiety almost completely. This was verified by the fact that the stress hormone level remained very close to normal in the presence of the person.
The conclusion that one can draw from this is that these dogs were behaving as if they had a stronger bond with their human caretaker then with their brother or sister, despite the fact that they been in the company of that dog for all of their lives. This was true even though these dogs have not led the same kind of living experience as a pet dog has, and therefore have not had continued intimate contact that pet dogs have with their human owners.
If we are to draw any comparison between dogs and wolves based on this research, it would be to note that dogs, like wolves, do have territories, at least in the sense that they feel most comfortable when they are in familiar places. We know that in the wild, wolves can move to new places without any rise in their stress levels, as long as they are in the company of members of their pack. The same is true of dogs, however it appears that the most significant pack member is likely to be a human (usually the dog's owner) and not another individual of its own species. For most dogs their owner has been a constant feature in their lives since they were puppies. It appears that we not only bred dogs to accept dogs and humans as relevant social partners, but to view humans as being more significant socially than other canines.
This has important implications for when dogs are being re-homed. Shelters often feel that dogs who have lived together in pairs must only be adopted out to a new home which is willing to take both dogs. If we extrapolate from the present research this seems like an unnecessary practice, as long as the home to which each dog is going has an individual human that the dog can bond with. Fortunately research has shown that dogs can quickly bond with a new human being based upon only a few minutes of friendly attention over a couple of days.
Dogs are not wolves. We now have data that suggests that we have selectively bred the domestic dog so that it is strongly biased to love humans (or at least one human) more strongly than it loves other dogs.