Cats’ ears, like ours, are instruments of both hearing and balance. The balancing function of cats’ ears is particularly unique, in that, combined with the cats’ remarkably supple spine, it enables them to twist and turn in order to land on their feet after falling from high places.
Cats’ sense of hearing is remarkably superior to that of humans. According to this article, cats’ hearing range (in Hz) is 45 to 64,000, compared to 64-23,000 in humans. This means that cats can hear sounds we can’t hear on both ends of the spectrum, particularly the higher end.