One of the hunters named Eckels gets scared when they see the huge dinosaur (this is why I called them so). They went back to the time to the time machine, which was also the way they got there, but Eckels he didn't stay in the special path provided by the time agency. So they don't mess with time and another thing the agency did is the hunters could only kill animals that have been ok'd by them which where marked with a red paint, Eckels what he did is he stepped out of this path and he killed a butterfly that wasn't ok'd by the agency at the time he didn't think much of this incident, because of this he change the past, present, and future of the earth and his future.
As the result of the time ripple effect the whole spelling and the president of the united states was changed, all because of some butterfly and some mud.
Ray Bradbury's short story "A Sound of Thunder" is a futuristic tale about the consequences of time travel and not following the rules established by Travis the guide and the rules of the travel agency and this affects the story because it changes time and the events of the future.