Toba Pilaga has a story of how a menstrating woman wouldn't stop bleeding until her husband (snakes) returned. When here man snake-children were killed, she, herself, turned into an iguana.

Bororo's story is possibly a continuation of the above:
"The girl married the man who killed her snake-husband. He gave her a piece of its flesh to cook, but the blood in it went straight through her skin and turned into a little snake in her womb. There it talked her into going into the forest every day so that it could [eat] ... the girl complained about this to her brothers who ambushed it on its next sortie, burnt the carcass and scattered the ashes, which grew into plants - into the urucu bush from whose fruit red paint is made, into the resin tree, into maize, cotton and tobacco" (p 14)