Climbing the social ladder is a ‘ruff’ business for dogs, new research from Europe shows.
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— from the University of Exeter in the UK, and by the Veterinary Service of the Local Health Unit Rome 3, Italy—observed the difficulty of working out the pecking order in the crowded middle leads to aggression.
“In the middle of the hierarchy—where it’s harder to predict which animal should be dominant—we see lots of aggression,” Dr Matthew Silk said.
Professor Robbie McDonald noted: “Fighting over food and mates uses energy and time and can lead to injuries, so hierarchies play an important role because animals know their place without needing to fight.”
The year-long study—published in the Proceedings of the Royal Society B: Biological Sciences—examined a pack of 27 mongrel dogs that roamed freely 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 sex, with adults dominant over younger dogs and males dominant over females of the same age group.
“Although fights within a social group of free-roaming dogs are usually characterised 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,” Dr Simona Cafazzo said.