Rays evolved from sharks. Today, there are about 500 different living species of rays and skate. The smallest ray is the Short-Nose electric ray, which is the size of a pancake. The biggest ray is the Manta ray which is over 6.7 m wide and weighs up to 1,350 kg. It is possible that a Manta Ray can grow up to a size of 9 meters. Most rays are in-between these two extremes. More than half of all ray species are over 50 cm long. Rays are some of the largest fish in the sea.