Answer: The llamas are moving their jaws.
Miguel Angel Asturias was a Nobel Prize-winning Guatemalan poet, diplomat, novelist, playwright and journalist. He drew attention to Latin American indigenous cultures, in particular those of his native Guatemala.
In this excerpt, he phrase "knitting their jaws" uses figurative language to describe the way in which llamas move their jaws. The author implies that this movement resembles that of knitting.
