However, whether such a sense of fairness evolved independently in capuchins and humans, or whether it stems from the common ancestor that the species had 35 million years ago, is, as yet, an unanswered question.
Whether they could then use this vocalization, these sounds that they produce now, whether they could then use them to interact with humans or with other killer whales is an open question.
And it's come to seem to me that the great challenges, all of the great challenges before our young century on some level are vast, aching open questions.