This paper presents a comparative study between the dynamic survivability approaches in WDM mesh networks. The paper focuses on the diverse routing and the p-cycle approaches to protect mesh networks against single span failure under dynamic traffic. The computational complexity and the blocking performances of both approaches are analyzed and compared. Simulation results suggest that the p-cycle approach has better blocking performance than the diverse routing approach. Additionally, the lower computational complexity of the p-cycle approach algorithm makes it more suitable, especially at highly dynamic traffic. As a result, the p-cycle approach scales better with the network size and the dynamic nature of the traffic than the diverse routing approach. Therefore, the p-cycle approach has presented itself as a better option than the diverse routing to solve the survivability problem in dynamic WDM wavelength-routed networks. Other advantages of the p-cycle approach include their fairness to requests with long routes.