Recent research in defense mechanisms against stealthy attacks in wireless ad hoc networks focuses on developing intelligent, adaptive, and cooperative techniques to detect and mitigate hidden or low-profile malicious activities that evade traditional intrusion detection systems. These attacks-such as selective forwarding, identity spoofing, wormhole tunneling, and colluding behavior—can severely degrade network performance and trust. To counter them, recent studies have proposed hybrid trust-based routing, lightweight anomaly detection using machine learning, and swarm intelligence-inspired models like ant colony or particle swarm optimization to identify subtle misbehavior. Cross-layer monitoring frameworks and blockchain-assisted authentication schemes are also being explored to ensure data integrity and resilience. Overall, the emerging trend emphasizes distributed, energy-efficient, and real-time defense strategies capable of maintaining secure communication in highly dynamic and decentralized ad hoc environments.