According to a description in the illustrated scrolls "Tonomine Engi Emaki", when Kamatari was born, a white fox with a sickle in its mouth appeared from somewhere and left the sickle at the foot of the newborn baby, thus the baby was named Kamako (kama meaning a sickle).
『多武峯縁起絵巻』には、鎌足が生まれたときにどこからか鎌をくわえた白い狐が現われ、生まれた子の足元に置いたため、その子を「鎌子」と名づけたと描かれている。