Actively swimming sharks and rays, such as the Manta, are believed to swim constantly, never stopping from birth to death.
Mantas and mobulas (also known as "devil rays", of which there are 9 species) are similar in form, sharing paddle-shaped cephalic lobes and gracefully curved pectoral wings.
Mantas and mobulas are most readily distinguished by the position of the mouth: in Mantas, the mouth is terminal (located at the front of the head), while in mobulas the mouth is subterminal (located underneath the head, as in many sharks).