What is this story from?

Question:

What is this story from?

"Once upon a time, a woman was picking up firewood. She came upon a poisonous snake frozen in the snow. She took the snake home and nursed it back to health. One day the snake bit her on the cheek. As she lay dying, she asked the snake, "Why have you done this to me?" And the snake answered, "Look, *****, you knew I was a snake."

Best Answer - Chosen by Asker:

as far as I can tell it's from the script of the movie "Natural Born Killers"...
INDIAN (navajo)
You want to hear the story too don't you old
man... O.K. (continues) She came upon a
poisonous snake frozen in the snow. She took
the snake home with her. She put the frozen
snake on her favorite blanket by the warm fire.
She fed it and nursed it back to health. One
day she picked the snake up and it bit her on
the cheek. As she lay dying she asked the
snake, I loved you, why have you done this to
me? The snake answered, "look *****, you knew
I was a snake."