The golden butterfly that Eckels steps on in his hurry back to the time machine represents the delicate balance of the natural world. It can also represent unforeseen consequences, mistakes, and points of no return. Being so tiny, the butterfly initially is not even noticed in the scuffle that ensues after the T. Rex is shot. It is therefore ironic that its death is the cause of the changes that follow. However, this kind of event is exactly what Travis warned against, and the clearest example of the importance of each element of an ecosystem. This is even more striking in comparison to the T. Rex’s death, which was not the cause of change. Instead, the seemingly insignificant death of the butterfly is the event that triggers the cascading effects that leads to Deutscher’s election.

The butterfly’s beauty, fragility, and tiny size contrasts with the T. Rex’s violent, huge, and intimidating presence. However, both the dinosaur and the butterfly have gold and green coloring. This similarity links the two and implies that their lives, deaths, and roles in the ecosystem are equally meaningful.

“A Sound of Thunder” has been wrongly credited as the origin of the “butterfly effect,” which posits that a tiny event—like a butterfly flapping its wings—could lead to the development of a major event, such as a hurricane.