Top dogs in a pack are known to assert their dominance, but scientists studied a group of free-roaming mongrels and found high levels of aggression in the middle of the dominance hierarchy. Most theories predict more aggression higher up the ladder. However, the researchers say that the difficulty of working out the ranking in the busy middle leads to aggression.
"Our results show the unavoidable costs of climbing a dominance hierarchy," the researcher said. “In the middle of the hierarchy – where it is more difficult to predict which animal should be dominant – we see a lot of aggression.” “Fighting over food and friends takes energy and time and can lead to injury, so hierarchies play an important role as animals know their place without having to fight.”
The years-long study examined 27 mongrel dogs roaming free in the suburbs of Rome. The dogs did not live with humans, although they relied on humans for food. Their hierarchy was based on age and gender, with adults being dominant over younger dogs and males dominant over females of the same age group.
While fights within a free-roaming dog social group are usually characterized by low-intensity aggression, the middle of the hierarchy is occupied by young males of similar size and age, among whom nothing is definitive and for whom the challenge is to gain rank. said the researcher. “Our results confirm that these dogs have an age-matched dominance hierarchy similar to that of wolves.”
Dominant behavior included a stiff, upright body with the head and tail set high and one paw resting on another dog's back.
Submissive behavior included avoiding eye contact, keeping the head and ears low, and lying with the chest and stomach exposed.
