Let's start with a Dr. Seuss classic - Horton Hears a Who.
Horton is an elephant who lives in the Jungle of Nool. The Whos are a race of people living on a dust speck. They ask Horton for his help and protection. Horton is the only one who hears them, and he does defend them, against a buzzard, some apes and a sour kangaroo.
Elephants are social and gregarious creatures. Although their sense of smell is keenest, they communicate with one another by sound. Elephants produce a number of sounds, but perhaps the most interesting is a low-frequency vocalization that lets herds and individual elephants keep in contact with each other. These sounds are loud and can be heard for 5 or 6 miles. But not by the human ear. To humans, the elephants aren't making any sounds at all.
So here's to elephants who listen so well they hear things we don't, perhaps even Whos. And here's to Horton who taught us, "a person's a person. No matter how small."