This paper reevaluates he multicas protocols for MANETs in terms of energy efficiency and proposes a new robust multicast protocol, called Two-Tree Multicas (TTM). Multicast protocols can be broadly categorized into two types, tree-based multicas and mesh-based multicas, based on the network structure along which multicast packets are delivered to multiple receivers. Mesh-based protocols are more robust to mobility and result in high packet delivery ratio. On the to her hand, multicast trees are more energy efficient than multicast meshes. This is because mesh-based protocols depend on broadcast flooding within the mesh and therefore, mobile nodes in the mesh must receive all multicast packets during the multicast communication. The proposed TTM uses two trees, a primary and an alternative backup tree, to improve energy efficiency compared to the mesh-based protocols and to offer a better energy balance and packet delivery ratio than the tree-based protocols. Performance evaluation study shows that the proposed TTM saves energy consumption by a factor of 1.9~4.0 compared to the mesh-based multicast. In terms of combined performance metric, energy per delivered packet, TTM shows up to 80% and 40% improved performance than the mesh-based multicast and the conventional shared tree multicast, respectively.