Art is defined as a work done by a human, with further description, depending on your source, to include specifics such as asthetically pleasing. I would update that to include animals. Some elephants, and primates have been known to be expressive with visual art. There are birds which apparently have only one set of sounds, without variance, but many are known to experiment, mimic, or steal new sounds. There is certainly natural occuring beauty, but it cannot be called art. While natural beauty has inspired a great portion of all art, it is the intentional act which defines it as art. In fact, quite a lot of art has no beauty, and is meant for shock value, or other emotional stimulation.