Flexi Says: Rays are a group of cartilaginous, jawed fish that are closely related to sharks. A common characteristic of rays are large pectoral fins that are fused to the head and used in a wing-like fashion, giving them the appearance of flying through water. Manta rays are the largest rays. The two known species of manta rays are giant manta rays and reef manta rays. Both are filter feeders with a diet composed mainly of zooplankton. Manta rays have been known to live up to 40 years.