Rays are cartilaginous fish, like sharks to which they are closely related. There are about 500 species belonging to 13 families.Their flattened body and their large wings make them graceful swimmers, certainly the most beautiful swimming that we can contemplate in Nature. For example, Manta rays feeding are as gracious as a real ballet. A wonder that only Mother Nature is capable of producing. Other species, such as torpedo rays, can create an electric field ranging from 60 to 230 Volt and reach an intensity of 30 Amperes