She often got angry at him, because she thought he was just ignoring her. Dogs can hear high notes Dogs and some other animals can hear sounds at higher frequencies than 20,000 Hz. That is why people can't hear a special dog whistle, while the dog will react to it. Being able to hear the higher frequencies may be useful in hunting for the animal. Cats probably can hear higher frequencies also, but most are too independent to respond to such a whistle.
Elephants can hear low notes Elephants can hear frequencies much lower than the range of humans.
Some researchers who were studying elephants in Africa discovered this. The story goes that a herd of elephants they were observing suddenly perked up their ear and ran off in a direction, as if they heard someone calling them. The researchers said they didn't hear anything, but some said they felt something strange in their bodies, just before the elephants ran off. After studying this situation, they found that elephants could make a very low frequency sound that humans can't hear. Elephants are able to hear this sound coming from up to 5 miles away.