In “A Sound of Thunder,” the butterfly is a symbol of the delicate ecological balance of the natural world. Although it is small, Bradbury reminds us, a butterfly—like every other creature—has its own role to play in the environmental order. The butterfly becomes the most visible manifestation of Mr. Travis’s warning that crushing even the tiniest creature could prove disastrous for all of humanity. While Travis does not specifically mention butterflies in his extended explanation of the dangers of interfering in the prehistoric environment, he names various small life-forms such as “a small bird, a roach, a flower even” as potentially important. The butterfly that Mr. Eckels crushes is, in a sense, the intersection of all of these things: a small, beautiful flying insect. It is so delicate as to have initially gone unnoticed in the aftermath of the hunt. Only after witnessing the subtle changes to the future’s atmosphere does Eckels think to check his boots and find the crushed insect. The butterfly’s green and gold coloration also echoes the description of the Tyrannosaurus rex, implicitly suggesting that its death is just as significant as the dinosaur’s.
Further, today’s reader may be reminded of “the butterfly effect,” a chaos theory term describing how small changes to a system can lead to broad and unpredictable consequences. This dynamic is played out in “A Sound of Thunder”: by stepping on and killing a butterfly, Eckels inadvertently changes the course of natural and human history. Through unknown means, the death of this small creature changes the result of the U.S. presidential election, illustrating the interdependency between humans and the natural world.
Butterfly Quotes in A Sound of Thunder
Not knowing it, we might kill an important animal, a small bird, a roach, a flower even, thus destroying an important link in a growing species. […] The stomp of your foot, on one mouse, could start an earthquake, the effects of which could shake our earth and destinies down through time, to their very foundations.
We can’t take a trophy back to the Future. The body has to stay right here where it would have died originally, so the insects, birds, and bacteria can get at it, as they were intended to. Everything in balance
Eckels felt himself fall into a chair. He fumbled crazily at the thick slime on his boots. He held up a clod of dirt, trembling. “No, it can’t be. Not a little thing like that. No!”
Embedded in the mud, glistening green and gold and black, was a butterfly, very beautiful and very dead.
“Not a little thing like that! Not a butterfly!” cried Eckels.
… “can’t we take it back, can’t we make it alive again? Can’t we start over? Can’t we—”
He did not move. Eyes shut, he waited, shivering. He heard Travis breathe loud in the room; he heard Travis shift his rifle, click the safety catch, and raise the weapon.
There was a sound of thunder.