Recent research in Energy-Efficient Routing Protocols for Mobile Ad Hoc Networks (MANETs) focuses on minimizing power consumption while maintaining reliable communication in dynamic, infrastructure-less environments. Modern studies integrate optimization algorithms such as Firefly, Whale, and Artificial Bee Colony (ABC) to select routes that balance energy usage across nodes and extend network lifetime. Hybrid models combining fuzzy logic, trust mechanisms, and QoS-aware routing further enhance energy efficiency and stability by considering link quality, residual battery power, and node mobility. Researchers are also exploring machine learning-based adaptive routing, where predictive analytics are used to estimate node energy levels and prevent premature node failures. Overall, current advancements in energy-efficient routing protocols emphasize sustainable, scalable, and intelligent communication strategies that reduce control overhead and prolong network operation in resource-constrained MANETs.