Full credit goes to my high school chemistry teacher. Cattle (and other ruminants) spend a lot of their time rechewing (or masticating) their "cud".
The etymology or aboriginal is basically "comes from away"; kind of Eurocentric. Indigenous means "comes from within a place" etymologically so while it is kind of semantic it's obvious which one is the better choice. Many indigenous people however prefer 'Indian' because it's how First Nations people are referred to in the Indian Act.
"What kind of decent, good-looking woman would want to go out with my son"