Elephants have padded feet, which make their steps virtually inaudible to their surroundings. Some researchers have remarked that they wouldn't hear a sound, and moments later, would be surrounded by hundreds of elephants.
“Elephants, it turns out, are surprisingly stealthy. As the sunlight fades, other species declare their presence. Throngs of zebras and wildebeests thunder by in the distance, trailing dust clouds. Cape buffalo snort and raise their horns and position themselves in front of their young. Giraffes stare over treetops, their huge brown eyes blinking, then lope away in seeming slow motion. But no elephants.” ― Thomas French, Zoo Story: Life in the Garden of Captives