Most of the ITS applications dedicated to vehicular networks rely on periodic messages sent in the vicinity of the vehicles. To ensure the road safety, the inter-messages delay admits strong constraints. The current standard proposes to adapt the inter-messages delay according to the vehicle dynamics. Nevertheless, when the density of vehicles is large, short delays may lead to collisions and losses, leading to a poor neighborhood knowledge accuracy. In this paper, we propose an adaptive strategy, named AND for Adaptive Neighbor Discovery, to take into account the networking conditions for updating the inter-messages delay. The aim is to detect the neighbors in time while preserving the network resources. We show that our cooperative approach achieves very good results in neighbor discovery while consuming less messages.