A manta ray is a large ray in the family Mobulidae. Mantas are the largest rays in the ocean, with the largest known individual measuring an impressive 25 feet (7.6 meters) at its widest point. Giant Pacific manta rays are often larger than people, leading to a widespread myth that these harmless fish attack divers. In fact, manta rays are very gentle and usually very shy, and they pose no threat to humans and most other organisms.
These fish have evolved from bottom-dwelling species. Although manta rays no longer hover around the ocean floor like their ancestors did, they have retained the flattened bodies associated with bottom-dwellers, along with the protective coloration of bottom dwelling species. On top, a manta ray is blue to black in color, making it hard to see when someone looks down on the ray through the ocean. On the bottom, manta rays are cream to white in color, blending in when viewed from below.
Manta rays are broader across than they are long, and they have distinctive fins near their faces which look sort of like horns, leading some people to call them “devil rays.” These fins are used to sweep in prey. Manta rays are filter feeders, living on plankton, and they are very adept swimmers, using their massive side fins like wings to sail through the water and steering with their whip-like tails. Some species can even jump totally out of the water.
The primary predator of the manta ray is the shark, although only very large shark species are willing to attack manta rays. Manta rays tend to live alone, but they form mutually beneficial relationships with parasitic fish which clean their bodies and gills for them at “cleaning stations,” areas around tropical reefs where parasitic species congregate. Cleaning stations operate like carwashes for fish, with fish in need of a cleaning swimming in to indicate that they need assistance, and a swarm of parasitic fish performing detail work, as it were.
The manta ray is ovoviviparous, which means that the females incubate their eggs in their bodies. Typically only one manta ray baby hatches at a time, and newborn manta rays are already around four feet (1.2 meters) across. Manta rays are found throughout the tropical waters of the world, especially around reefs, which means that many visitors to these regions come into contact with manta rays. Although it might be tempting to imagine grabbing on and hitching a ride with these fast swimmers, people should avoid handling manta rays, as they can hurt them or damage the mucus membranes which protect the body from infection.