When the hunters arrive at their destination what does Travis tell them hasn't happened yet in history in A sound of thunder?

In Ray Bradbury's "A Sound of Thunder," when the hunters arrive at their destination, Travis informs them that the dinosaurs they are about to hunt have not yet gone extinct. He emphasizes the importance of their mission and the need to avoid any actions that could alter the timeline, highlighting the fragile nature of history. This sets the stage for the tension and stakes involved in their time-traveling adventure.