Interesting Facts About the Manta Ray

In 2008, a huge manta ray was discovered on the pavement of San Francisco, which was later rescued and returned to the water by the government authorities.

Manta rays are eagle rays that belong to the genus Manta. There are mainly two species of rays that belong to this genus - the Manta birostris and the Manta alfredi. The Manta birostris is the larger ray that is also known as the 'Giant Oceanic Manta Ray'.

The other species, Manta alfredi, is commonly known as 'Reef Manta Ray'. Another species of manta ray is suspected to live in the Atlantic, but so far not much is known about this species.

Manta rays belong to the family Mobulidae, and the subclass Elasmobranchii, which also includes sharks and other rays. The members of the Manta genus can be distinguished by their triangular pectoral fins, forward-facing mouth, and their graceful gait.

Manta rays gently glide through the water with the help of their wide pectoral fins, that resemble the wings of a bird. The name 'manta' is of Spanish origin, which means a 'cloak' or a 'blanket'. True to its name, a manta ray swimming in water actually resembles a blanket moving in the water.

✦ On an average, manta rays can reach a width of 3 to 7 meters, with some larger specimens recording a width of more than 9 meters. Mantas can weigh around 3,000 pounds. The giant oceanic manta ray is the largest type of ray in the world.

✦ The magnificent manta ray is characterized by a flat, disc-like body, and a broad head. The eyes are located on either side of the head, near the cephalic fins. The small dorsal fins are located at the base of the whip-like tail, which is much shorter as compared to the size of its body.

✦ As mentioned already, the pectoral fins of manta rays are triangular-shaped, while the cephalic fins are horn-shaped and located on either side of the mouth. The horn-shaped fleshy cephalic fins are used to direct plankton-rich water to their broad and wide mouth.

✦ Manta rays also possess five gill slits on their ventral surface, where the modified denticles are present. These denticles are used to filter plankton from water.

✦ Dorsally, mantas are black, gray-blue, or red-brown in color, while their ventral surface is generally pale or white-colored. They also possess shoulder patches and blotches on their stomach. In fact, the pattern of these blotches exhibits individual variations just like human fingerprints. In other words, each manta ray possesses distinct and unique spots on its stomach, which helps in its identification.

✦ The two species of mantas can be distinguished by the variation in their color patterns, dentition, and the dermal denticles found in the gill slits. The Manta birostris is characterized by larger spots or blotches in its ventral surface, a dark-colored mouth, angular shoulder markings, and overlapping denticles with multiple cusps.

✦ The Manta alfredi, on the other hand, possesses rounded shoulder markings, a white or pale-colored mouth, and evenly spaced denticles without any cusp. The ventral spots of this manta ray are located near the posterior end.

✦ Male manta rays can be identified by the presence of a pair of external claspers at the base of their pelvic fin, which are not found in female mantas.

✦ Another interesting fact about manta rays is that their skeletons are not composed of bones, like other fish. Instead, they possess a cartilaginous skeleton.

✦ Manta rays can usually be found in tropical and subtropical waters, around 35 degree north and 35 degree south of the equator. They can be found in all the major oceans of the world.

The coral reefs are the 'cleaning stations' for manta rays, where they remain motionless for several minutes, while the fish eat the parasites living on their body.

✦ Like sharks, manta ray exhibit internal fertilization. At the time of mating, the female manta ray is chased by several males, that line-up behind her forming the 'mating trains'. Finally, the female chooses one male to mate with her. It is believed that the mating process in manta rays may be triggered by a full moon.

✦ The fertilized eggs remain inside a female manta ray for 12 to 13 months. In the beginning, the eggs remain enclosed within a thin shell or egg case. Eventually the developing embryos absorb the yolk. The manta ray is an ovoviviparous animal, and hence, the eggs are hatched within the uterus of the female. The females give birth to live young ones called pups.

✦ A female manta ray gives birth to one or two pups in each pregnancy. The pups are usually 1.5 to 2 meters wide and weigh approximately 45 kg at the time of birth.

✦ The manta ray is a filter feeder, and uses its gills to retain the plankton and small fish that enter its mouth along with water. The plankton is then siphoned off to the stomach by the gill arches.

✦ Like whales, manta rays display amazing acrobatics by leaping out of water, and sometimes, flipping or somersaulting before finally landing in water with a loud slapping sound. The reason behind this behavior is not known, though it is speculated that these acrobatics could be a way to communicate, attract mates, or remove parasites and remoras.

✦ Remoras are suckerfish that remain attached to the mantas with the help of a large sucking disc located on top of their head. They do so to feed on skin parasites and small pieces of food particles dropped by the manta ray.

✦ The manta ray possesses the largest brain-to-body ratio among all sharks and rays.

✦ Manta rays are known to have a gentle disposition, though they are commonly called 'devil rays'. The fish earned this nickname due to the shape of their cephalic fins, which resemble devil's horns.

✦ The mucous membrane that covers the skin of manta rays actually
help protect it from infections. But this membrane is so delicate that it can get destroyed when touched by humans.

✦ On an average, manta rays can live for about 20 years, while
some mantas may live up to 50 years. It is believed that manta rays developed from bottom-dwelling stingrays, but do not possess stingers like stingrays.

✦ Both stingrays and sharks are close relatives of mantas. But ironically, sharks are also the main predators of manta rays, along with orcas.

✦ Manta rays are excellent swimmers, and it is believed that they may be able to remember their 'cleaning stations' and feeding grounds. Individual mantas may return to the same cleaning station and feeding ground again and again.

✦ Manta rays evolved around an estimated 20 million years ago, but the fossil records of true mantas date back to about 4.8 million years.

In November 2011, the IUCN (International Union for the Conservation of Nature) declared giant manta rays Vulnerable with an Elevated Risk of Extinction, while reef mantas were listed as Vulnerable. Manta rays have low reproductive rates, and moreover, they are hunted for their skin and liver oil, mainly in Australian and US waters.

In Philippines, the meat of a manta ray is considered a delicacy, while in China the gill rakers of this fish are used for medicinal purposes. Due to all these factors, the population of manta ray is declining in certain parts of the world, especially in the Gulf of California, South China, Sulu Seas, and the west coast of Mexico.

Manta rays are a common sight in the tropical waters of Australia and Maldives. In fact, the Republic of Maldives is one of the places where you can spot mantas in large numbers. In the Ningaloo Marine Park of Australia, you can not only see manta rays, but can have the privilege of swimming with this amazing fish.

Apart from the Ningaloo Marine Park, you can also see mantas in the Muiron Islands Marine Management Area, Montebello Islands Marine Park, and the Rowley Shoals Marine Park of Australia. In addition to Australia and Maldives, you can spot manta rays in the waters of Hawaii, Mexico, Indonesia, Bahamas, Thailand, Fiji Island, and Palau.