Criminal Swarms. An Evolutionary Explanation of the Resilience of Rio De Janeiro’s Trafficker Gangs

In Rio de Janeiro, non-state armed groups have become a permanent and widespread presence ever since the 1980s. Decades of repression by police forces have failed at eradicating them. The ineffectiveness of the Brazilian state is puzzling, given the large imbalance of forces in its favour, the high visibility of criminal violence, the rudimentary organisation of non-state groups, and the almost non-existent public support for the latter. This paper will seek to explain why these groups have shown resilience despite all these negative conditions. To do so, the paper will adopt an evolutionary/ecological outlook: evolutionary, because it aims at explaining the causes of change over time; ecological, because it aims at offering an encompassing view of all factors contributing to resilience and adaptness. Through this outlook, the paper will argue that gangs have become resilient by unconsciously adapting to environmental threats. They did so by becoming gradually less organised and less dependent on rigid hierarchies and leadership. This paper will firstly present the main features of Rio’s trafficker gangs and the history of the repressive efforts against them, highlighting the puzzle of their failure. It will then expose the foundations, aims, and components of the evolutionary/ecological outlook, stressing why it is suitable to this study. The paper will then proceed to review the main characters of state repression in the past 25 years: these characters remained remarkably constant over time, effectively constituting a regular selection pressure on trafficker gangs and their members, particularly their leaders. As an effect of this selection pressure, criminal groups had to change in an unconscious, unplanned manner by gradually disorganising. This change made gangs more resilient and allowed them to continue their operations. The paper will finally assess the potential of the evolutionary/ecological outlook in advancing a comprehensive understanding of change within criminal organisations.