Abstract. This paper presents a novel swarm intelligence inspired routing algorithm, emergent ad hoc routing algorithm (EARA), for mobile ad hoc networks. Based on the understanding of the evolutionary cooperation in the biological swarm, which provides an alternative solution resilient against changes in the dynamic environment, we use the principle of swarm intelligence for the reinforcement of optimal routes with only local communication (here, local communication is defined as the neighbour-to-neighbour Communication). The data traffic is influenced at each node, and the communicating nodes observe this influence to update their tables. The concept of stigmergy is adopted to reduce the amount of control traffic to improve the performance of the system. We also include an evaluation methodology to simulate ad hoc networks, and the simulation results show that this routing algorithm scales well to a variety of network conditions.