The locations of the inscrutable stone heads of Easter Island, or Rapa Nui, beg for some kind of explanation. Now, researchers say many of the statues, called moai, are located near freshwater, The Guardian reports. On Rapa Nui, fresh groundwater seeps into caves and aquifers and typically emerges at the coast, where the majority of the moai are found. The size and number of the statues may also correspond to the quality or quantity of the freshwater resources, the researchers report in the journal PLOS ONE. However, other scientists say there still isn’t enough evidence to link these sources of water to the mysterious moia.