From an article New York Times Art Section, Nov 4, 2008 by Douglas Martin"

"Yma Sumac, a Peruvian singer who burst on the American scene in the 1950s in a tornado of exotic publicity with a voice that glided preternaturally across four octaves", died on November 1st, at the age of 86.

"She received no formal music lessons saying “...the creatures of the forest taught me how to sing." "She spoke of jungle animals as musical influences."

“She sings very low and warm, very high and birdlike; and her middle range is no less lovely than the extremes of her scale,” Virgil Thomson wrote in The New York Herald Tribune in 1954. “That scale is very close to four octaves, but is in no way inhuman or outlandish in sound.”
Article/obituary (By Douglas Martin)