: Traditional ad hoc routing protocols do not work in intermittently connected networks since end-to-end paths may not exist in such networks. Hence, routing mechanisms that can withstand disruptions need to be designed. A store-and-forward approach has been proposed for delivering messages in disruption tolerant networks. Recently, several approaches have been proposed for unicast routing in disruption-prone networks e.g. the 2-hop relay approach, delivery probability based routing, and message ferrying schemes. In our earlier paper, we have evaluated a combined multihop and message ferrying approach in disruption tolerant networks. In that paper, we assume that a special node is designated to be a message ferry. A more flexible approach is to let regular nodes volunteer to be message ferries when network dynamics mandate the presence of such ferries to ensure communications. Thus, in this paper, we design a node-density based adaptive routing (NDBAR) scheme that allows regular nodes ...