Wireless sensor networks are susceptible to various kinds of security threat. Node replication attack is one of them. In this attack, an adversary captures a node and deploys a number of replicas in the network to launch further attacks. Detection of replica is a challenging task especially when the nodes are mobile. Only a few techniques are reported in the literature for detecting replicas in mobile wireless sensor networks. They are mostly centralized detection mechanisms, where the base station plays a major role in clone detection. In this paper, we propose a distributed replica detection mechanism called energy-based replica detection. Every node in the network acts as a monitoring node to a set of nodes in the network. Replicas are detected on the basis of the residual energy of nodes. A conflict in the timestamp-residual energy pair of a node is detected as clone by its monitoring node. We have simulated and compared the proposed scheme with Efficient Distributed Detection and Multi-Time-Location Storage and Diffusion scheme. We observed that the proposed scheme has higher detection probability, and lower communication and storage overhead. Copyright © 2014 John Wiley & Sons, Ltd.