In the year 2055, Mr. Eckels enters the office of Time Safari, Inc., a company that offers trips to the past in order to hunt large prehistoric animals—including dinosaurs—for the price of ten thousand dollars. Eckels feels phlegm gather in his throat as he asks the company agent behind the reception desk whether the company guarantees he will come back alive. The agent informs him that there are no guarantees “except the dinosaurs,” and that if Eckels disobeys any instructions he will be fined another ten thousand dollars.
Although he is excited about the safari, even upon entering the office Mr. Eckels worries about the possibility of dying on the trip. As company policies lay out, however, there is no certain outcome to these trips. The agent’s emphasis on uncertainty gives Eckels pause, but not enough to prevent him from seeking this ultimate achievement of control over nature. This moment establishes the importance of following instructions, foreshadowing Eckels’s later fatal transgression.
Eckels takes a moment to admire the Time Machine and remember the company’s advertisements—which, he recalls, tend to focus on the reversal of life and death. Eckels muses that with only “a touch of the hand,” gray hair and wrinkles could disappear; everything could “fly back to seed, flee death, rush down to their beginnings.”
Eckels makes small talk with the company agent while waiting, discussing the recent presidential election in the United States. Eckels expresses relief that Keith was elected rather than Deutscher. The official agrees that Keith is the best candidate for American and democratic values, asserting that Deutscher—“a militarist, anti-Christ, anti-human, anti-intellectual”—would have brought about dictatorship. The agent adds that people have called the company only semi-joking that if Deutscher won they’d want to go live in 1492; however, it’s not the company’s “business to conduct Escapes,” the agent adds.
This portion of the story introduces the theme of authoritarianism. The presidential election represents a classic conflict between American democracy and totalitarian regimes. The German name Deutscher hints at connections with Nazi Germany but many of the values described could also refer to American views on Soviet Russia during the Cold War. The agent’s comment that the company does not conduct “Escapes” foreshadows the dark political direction this story will take and the inevitability of authoritarianism.
The company agent asks Eckels to sign a release, reminding him that the dinosaurs he’s going to hunt are highly dangerous. Eckels responds in anger, but the official explains that the spiel is designed to scare of those not looking for “the severest thrill a real hunter could ever ask for.” The agent mentions that a number of clients and safari guides have died on the trips and offers Eckels the chance to tear up his check. Eckels hesitates, his fingers twitching, but the agent continues the transaction.
The agent’s statements about the danger involved in the hunt seem almost designed to provoke Eckels into showing his bravery—really, his bravado. His line about a “real” hunter implies that anyone who is not up for facing such a frightening prospect is not truly a hunter. Further, Eckels hesitates and never clearly affirms his intent to go on the safari, but the process seems to move forward in the absence of a decision. This echoes the way his actions in the past will start a chain of events over which he ultimately has no control.
The company agent hands Eckels over to the safari guide Mr. Travis, although it is unclear whether Eckels has actually stated that he would like to continue on the safari. The Time Machine begins to flash backwards through the years as the hunters and guides test out their oxygen and intercoms. Eckels sits stiff and pale alongside Mr. Travis, fellow guide Lesperance, and two other hunters.
Eckels appears filled with more than usual foreboding in this moment. He seems almost to have no agency, as if this adventure is happening to him rather than by his own choice. This again reflects the story’s broader sense of events being unpredictable and largely beyond human control. Further, his stiff and pale demeanor is almost corpse-like, adding to the many associations of Eckels’ character with death.
Eckels nervously contemplates the rifles they all hold, tightly gripping his own gun. He asks Travis if the guns can “get a dinosaur cold.” Travis responds equivocally, noting that some dinosaurs have two brains and are too risky to hunt. He counsels Eckels to shoot for the eyes and into the brain.
Eckels continues to display his nervousness about the deadly potential of the prehistoric environment. He seeks control over the situation. Travis’s response underscores the fact that, even given the number of precautions the safari company takes, outcomes are not entirely certain.
Eventually, the flashing of day and night outside comes to a halt, the sun standing still in the sky. The fog gathered around the machine clears to reveal a prehistoric wilderness.
Through the height of human technology, the hunters find themselves in the midst of a vast and wild natural environment. The stillness of this moment is anticipatory, building interest in the action yet to come.
Travis begins a speech emphasizing that the travelers are now far, far in the past, listing the historical figures who have not yet been born. He exhorts the hunters to stay on the metal Path that hovers over the ground in order to prevent stepping on any important plant or animal and disturbing the natural environment. He reminds the hunters that there is a huge fine for anyone who fails to obey the rules.
Travis’s speech serves to illustrate just how pristine this wilderness is, untouched by the march of human history. His reminders to the hunters are a part of Time Safari, Inc.’s efforts to control the outcome of their hunts and to protect the natural environment from interference.
Eckels expresses his confusion at the rules, prompting Travis to launch into a long explanation. The guide details a long list of potential blunders and their effects, such as stepping on one mouse and disrupting an entire future food chain. Crushing even the smallest life form, he explains, could disrupt ecological balance and change the future, not just of nature, but of human society. Eckels takes a somewhat adversarial role during this exchange, constantly questioning the connections that Travis draws between cause and effect.
Travis demonstrates a firm grasp of the idea that small changes may snowball into huge unintended consequences. Eckels, meanwhile, remains fixated on what he perceives as the disproportionate relationship between tiny organisms and the broad arc of human history. “A Sound of Thunder” puts Eckels’s and Travis’s competing theories to the test.
Seemingly grasping the rules at last, Eckels asks which animals are okay to shoot. Lesperance explains that the party can safely shoot the specific animal he has previously marked for them, because he has already traveled back in time to find a creature that would have died of some accident within minutes after the hunt regardless. Hearing this, Eckels reasons that Lesperance must know about the success or failure of the expedition. The guide explains that there is no way to know because one cannot meet oneself while traveling through time.
Time Safari Inc.’s precautions seem both extreme—multiple trips back in time to find one dinosaur—and insufficient. After all, they may be picking a creature destined to die, but who is to say that shooting the dinosaur will not cause it to fall slightly differently, and land on an insect or a flower that would otherwise have played a crucial role in history? This suggests the company’s hubris in its belief that it can entirely control the conditions of the safari. Eckels once again finds himself wishing for certainty and baffled by the safari leaders’ simultaneous precision and lack of pertinent information.
Eckels messes about with his gun a bit while waiting and Travis scolds him not to aim at anything but the dinosaur. Lesperance signals that the T. rex will soon approach. Eckels begins to muse on the incongruity of a moment when neither the new president nor any of the people celebrating exist yet. Soon the forest goes quiet, and the T. rex approaches with a sound of thunder. Eckels is transfixed when he comes face to face with the creature. Observing its massive, machine-like body, he proclaims it impossible to kill and wishes to retreat.
In the lead up to the encounter with the dinosaur, Eckels acts excited, almost playful. He marvels at the strange circumstances. Travis, on the other hand, braces for a serious encounter. The T. rex’s approach, heralded by a booming sound like thunder, brings a very real possibility of death into the narrative. This “sound of thunder,” appearing twice in the story, becomes a symbol of mortality and the inevitability of death.
Travis tries to silence Eckels, then directs him to wait in the Time Machine and promises to refund half his fee. Eckels, recoiling in horror from the creature’s metallic, insect-crusted hide, proclaims, “It was never like this before. I was always sure I’d come through alive.” Lesperance reiterates the instructions to wait in the machine. Instead, dazed and unable to follow directions, Eckels wanders off the path while the guides and the other two hunters shoot at the dinosaur bearing down on them. Despite the fearsome sight it presents, the T. rex falls dead, and the jungle is silent.
Eckels, as a big game hunter, seems to have fancied himself as brave, even fearless. He realizes in looking at the fearsome T. rex that he cannot face true uncertainty as to whether he will live; he only enjoys hunting when he has clear control over his prey, and the story insists that human beings overestimate their power at their own peril. The dinosaur seems almost beyond life, its body both machine-like and reminiscent of decomposition. In trying to avoid death, Eckels makes the fatal mistake of interfering with the prehistoric wilderness. His error will change the course of history.
The hunters and guides are all profoundly effected by the creature’s bloody end, some cursing and others vomiting in disgust. Travis returns to find Eckels shivering on the floor of the Time Machine. He retrieves supplies for the other hunters to clean the creature’s blood off themselves as they observe the carcass. The body settles into the stillness of death like “a wrecked locomotive or a steam shovel at quitting time.” Lesperance offers two hunters who shot at the dinosaur a chance to pose for a photo, explaining that they cannot take any trophies with them. They decline, and all return to the Time Machine to find Eckels still huddled on the floor.
The T. rex’s death is horribly gruesome, leaving even the less squeamish safari goers shaken. Travis appears hardened and unconcerned with Eckels’s panic attack. This scene poses an implicit critique of trophy hunting, both in terms of the horrors it brings and for the ways that it hardens people. The men who paid to go on this trip leave with not even a souvenir, nothing but the bloody memory of an incomprehensibly large creature destroyed.
Eckels finally says, “I’m sorry.” Travis, realizing that Eckels wandered off the path, yells and him and threatens to leave him behind. He is incensed that Eckels would violate the rules and put the business at risk of fines or even being shut down by the government. He eventually orders Eckels to retrieve the bullets from the dinosaur carcass. Lesperance scolds Travis for this, telling him that it was unnecessary, but Travis is unconvinced. He rants about the uncertainty of what parts of the future Eckels might have changed.
Even Travis, who seems to understand the dangers of time travel and the unpredictability of cause and effect better than anyone, is primarily concerned about the bottom line. Although not spelled out, it seems that leaving Eckels in the past (perhaps claiming that he was eaten by a dinosaur) might be a way around government reprimands for the company. Only as an afterthought does he mention the potential environmental and historical damage.
When Eckels returns, covered in blood, they leave for the future. Lesperance suggests the punishment was unnecessary, but Travis claims that it will prevent Eckels from hunting “game like this” in the future. Travis threatens Eckels, who protests his innocence, sure that his brief lapse could not have changed anything.
Neither Lesperance nor Eckels want to believe that a small error like stepping off the path could lead to any major changes. Travis is skeptical of this optimism, and he maintains his anger over Eckels’s lapse in judgment.
When they arrive, Travis observes the office with suspicion. Assured by the company agent that everything is alright, he orders Eckels to leave and never come back. Eckels, however, lingers for a moment, noticing that the atmosphere and small things about the office have changed. The air smells different; the colors are ever so slightly off; and, most tellingly, the sign over the desk is written with a different spelling system.
Travis is eager to get rid of Eckels, but Eckels finds himself jarred out of hopeful optimism by the realization that this is not quite the same future that he left behind. His senses all tell him there are small, almost intangible differences in the atmosphere, while the sign confirms that human culture has changed as well. Apparently, his venture off the path has changed something after all.
Eckels slumps down into a chair and, examining his boots, finds that he has crushed a small butterfly. Its green and gold wings glisten as his mind races with thoughts of dominoes, wondering how something so small could change the future. Panicking, he asks the company agent about the election results and learns that Deutscher has now won.
The butterfly represents chaos. It is the tiny, delicate element that nonetheless changes everything. Its green and gold coloration recalls the T. rex, setting up parallel instances of environmental destruction. Even this tiny casualty of negligence can have a huge effect—in this case, it has brought about the very authoritarianism that Eckels joked about escaping. This passage contains many interlocking ideas, including the perils of carelessness with nature, the ever-present threat of fascism, the unpredictability of consequences, and the unseen value of every life.
After a few moments of pleading to go back and fix things, Eckels waits in silence, eyes closed. He hears Travis take a breath, raise his rifle, and release the safety on his gun. The story ends with a sound of thunder.
Eckels’s desire to go back and fix what he has broken is too little, too late. All that is left is retribution. The sound of thunder in this passage, echoing the sound of the T. rex bearing down on the hunting party, likely represents a gunshot, with Travis killing Eckels to punish him for his mistake—and to destroy the evidence.