Dogs laugh, but they laugh with their tails. What puts man in a higher state of evolution is that he has got his laugh on the right end.

Eastman’s quip hinges on a playful anthropomorphism: dogs “laugh” through bodily expression (the wagging tail), while humans externalize amusement through the face and voice. The joke about having one’s “laugh on the right end” is a comic way of asserting that human evolution is marked not merely by feeling joy but by where and how it is expressed—through speech, social signaling, and shared understanding. Beneath the humor is a claim about culture: human laughter is communicative and communal, tied to language and self-awareness, whereas animal “laughter” is read as instinctive gesture. The line also satirizes human pride in evolutionary superiority by reducing it to anatomy and placement.