Elephants Communicate Through the Ground

Several elephants would freeze simultaneously, sometimes in mid-stride, and would press their front feet into the ground. They might also roll a foot forward so that only their toes touched the ground. At other times, they would lift a front leg. … For example, they responded appropriately to an alarm call from another elephant by assuming their defensive posture of bunching and freezing. Elephants can close their middle ear canal, forming a closed acoustic tube which enhances bone conduction and blocks out acoustic sound, helping the elephant focus on the vibration pathway. They have an acoustically designed foot, with a thick fat pad that perhaps helps in the transmission or conduction of vibrations.

via How elephants ‘talk’ to each other through the ground.