Female elephants spend their entire lives living in large groups called herds. Male elephant leave their herds at about 13 years old and live fairly solitary lives from this point.
"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.