Are the Top Dogs on the Social Ladder Targets of Aggression?
Dogs respond differently than humans to differences in social rank.
Posted Jul 17, 2019 | Reviewed by Gary Drevitch
Among humans, your social rank determines how people behave toward you—for example, whether they show you respect or whether they snipe, take pot shots, or plan overt aggression toward you. The same holds for dogs. The rank of any canine in a group of dogs determines the likelihood that that individual may become the subject of aggressive behavior by other individuals in the pack. However, the way that this works itself out seems to be quite different among canines compared to the way that it happens among humans.
Take, for example, the popular belief that it is dangerous to be at the top of a social hierarchy. As Shakespeare put it in Henry IV, "Uneasy lies the head that wears a crown." This aspect of human behavior for humans was graphically illustrated in the TV series Game of Thrones. In that fictional world, whoever happened to be holding the throne became the prime target for both opportunistic and planned aggression by others seeking to become the most powerful. Many social psychologists believe this is the natural order of things in societies that have a social ladder or a dominance hierarchy, with the current leader always in a precarious situation with many rivals. In addition, social psychologists are likely to note the corollary, which is that the people at the bottom of the social hierarchy are also highly likely to be the recipients of aggressive behavior, which seems to be substantiated by studies done in high schools where the "losers" are bullied unmercifully. But according to some new data, patterns of aggression triggered by relative social rank are quite different in dogs.
This research was carried out at the University of Exeter in the U.K in conjunction with the Veterinary Service of the Local Health Unit in Rome, Italy. From an experimenter's point of view there is a practical problem if you want to study social hierarchies in domestic dogs: Even in households which have multiple dogs as pets, you only usually have only two or three dogs in a home, and that is really not enough to allow you to explore social relationships based on hierarchy in any detail. You need a sizable bunch of dogs, living together and interacting without interference in order to tease apart how social rank affects behavior in a group. The researchers took advantage of the fact that free-living packs of dogs live in Rome. These dogs are not owned by humans, nor do they socialize with humans, and so they move, interact, and breed without interference. However, these dogs are dependent on humans for food, which is provided daily by volunteer caretakers. The particular pack chosen for study ranged in size from 25 to 40 dogs, but the analysis focused on 27 individuals that remained in the pack long enough to provide sufficient behavioral data. The study involved a long, taxing period of data collection totaling 197 days of observation over the period of a year, as well as complex statistical analyses.
The ranks of individual dogs were determined by observing typical ritualized dominance behaviors which show up in body language. Thus, dominant dogs display an upright and stiff body posture, with their head and tail held high and their ears pricked. High-status dogs will often place their muzzle or paw on another individual's back to physically demonstrate their higher rank. Dogs lower on the social ladder show much more submissive behaviors, including avoidance of eye contact, holding their head down, flattening their ears, holding the tail down or tightly between the hind legs, cringing, lying down and exposing their belly and throat, or simply retreating when approached. The number of dominant and submissive behaviors could be tallied and indexed to place a dog's rank in the social hierarchy.
In wild wolf packs, the dominance relationships are often set up much like that in a human family, where the adult breeding pair has the highest dominance (much like parents) and the remaining individuals assume positions on the social ladder based on their age, sex, size, and temperament. In the case of this free-ranging pack of dogs, the researchers found that there was a nearly linear hierarchy starting from what we might call the top dog and systematically moving downward in a stepwise manner until one hit the lowest-ranked canine. Much like in the wolf packs, adults occupied the top ranks of the hierarchy and juveniles occupied the lowest ranks. It is also the case that males tended to be higher ranked than females of the same age.
As might be expected, there were numerous instances involving aggressive squabbles, but generally speaking, these were short and of low-level intensity. As one of the authors, Robbie McDonald, notes:
"Fighting over food and mates uses energy and time and can lead to injuries. So hierarchies play an important role because the animals know their place without needing to fight."
However, the dogs in a pack do occasionally fight, so we can ask if it's the top-ranked dogs that are singled out for aggression (as in Game of Thrones), or the bottom-ranked dogs (as in high school bullying patterns)? It turns out that dogs are not like humans, and most of the infighting and aggression occurs between those dogs in the middle of the pack. These are animals that are quite close to each other in terms of their social ranking. The most dominant dogs are seldom the targets of any form of aggression, so it is quite safe to hold a high rank in a canine hierarchy. At the same time, the dogs at the bottom of the social ladder are rarely singled out as targets of attacks, which means that even though they have little status, the "losers" are out of harm's way.
The lead author, Matthew Silk, summarized the team's findings:
"Our results reveal the unavoidable costs of climbing a dominance hierarchy. In the middle of the hierarchy — where it's harder to predict which animal should be dominant — we see lots of aggression."
So, contrary to Shakespeare, we can say, "Easy lies the head that wears a crown"—if you are a dog.
Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission
Silk MJ, Cant MA, Cafazzo S, Natoli E, McDonald RA. (2019). Elevated aggression is associated with uncertainty in a network of dog dominance interactions. Proceedings of the Royal Society B, 286: 20190536. http://dx.doi.org/10.1098/rspb.2019.0536