Though nobody has ever seen two dogs making an exchange, yet a dog has been often seen to hide a bone. The dog does this from a sense of its value, properly so called. He does not do it merely from a sense of utility, or, in other words, because he likes a bone, but because he knows that a bone is a good thing which is not always to be had when wanted.
William F. Lloyd, “A Lecture on the Notion of Value as Distinguished Not Only From Utility, but also from Value in Exchange” (University of Oxford, 1833).