In Mesopotamian religion , the city god of Girsu.
The son of Enlil and Ninlil, he was the god of thunder and of the spring rains and floods as well as the god of the plow. His original name was Imdugud ("Raincloud"), and his earliest form was that of the thundercloud represented as an enormous black bird roaring its thunder cry from a lion's head. Eventually Ninurta was given human form, and his original shape was assigned to his ancient enemy. His festival marked the beginning of the plowing season.