Manta Ray

Manta Rays are large eagle rays that belong to the Manta class. The largest manta ray is Manta Birostris. It has a wingspan up to 7m and weigh up to 2 tonnes. On the other hand the smaller one, Manta Alfredi is only 5.5m and weigh about 1.5tonnes. Both of these mantas have triangular side fins or pectoral fins that they use to propel themselves through the water. They live in the temperate, subtropical and tropical waters. The furthest north they have have been is South Carolina, United States (31 degree north) and the furthest south is North Island of New Zealand (36 degree south). They prefer water with the temperature above 20 degree celsius. They swim close to the surface and in shallow water during the day, but at night they will swim deeper into the ocean.The upper surface of their flat body is grey to black and their underside are usually covered with some spots.

The word ‘manta’ which is Spanish for ‘blanket’ describes the graceful large manta very well. They are very acrobatic. They can even leap from the water like a skilful acrobat in the circus. Mantas are also known as ‘devilfish’ because they have a horn shaped cephalic fins on their heads which make them look evil. These horn shaped cephalic fins are located on either side of their mouths. They have broad heads. You will be amazed to know that their brain takes up more of their body than most other fish. Their brain has some special blood vessels that will keep them warm in the water.

Manta rays do not look like a fish. But they are actually a fish. They belong to a group of fish which have cartilage instead of bone. They have tough cartilage like sharks. They have a large rectangular mouth which face forward. They can’t stop swimming if they want to stay alive. They have to swim continuously to keep oxygenated water passing over their gills. They must be pretty fit to swim all the time! They locate their prey by sight and smell.

The mother manta rays give birth every year. She lays a couple of eggs which actually develop and hatch inside her. Within 6 weeks of hatching mother manta will give birth to 1 or 2 manta ray pups. The pups arrive rolled up. They have a width of 192cm long and weight of 70kg. They remain in shallow water for a few years before heading to the deeper sea. Manta rays may live up to 50 years.

Manta ray have different ways of swimming at different habitats. They will swim at a constant rate in a straight line when they are in deep waters. But when they are close to the shore, they will usually swim lazily. They travel alone  most of the time. They can also be seen travelling in groups of 50. They make friends with other fish, sea birds and marine mammals.

Mantas eat microscopic shrimp, plankton and small fish. They eat about 13% of their body weight each week. They funnel the food into their mouths while they swim, using 2 large, flap-lilke cephalic lobes which extend forward from their eyes. Excess water is sieved out through the mantas’ gills.

They have no teeth like a shark. All they have is a stripe of very small low teeth on their bottom jaws that looks like sandpaper. Despite of their large size, they are not aggressive. They do not have stinger like stingray. They are harmless to people. In fact they are preyed upon by a number of large marine predators like great white shark, killer whales and also humans.

They are very clean creatures. They visit the cleaning station which is situated at the seabed regularly to be cleaned. The cleaning process includes the removal of parasites from their body. For example, in Mozambique , sergeant major fish clean the mouth while butterflyfishes clean the bite wounds on the manta’s body.

Today, manta rays are affected by pollution in the water, global warming and overfishing in some areas, therefore there is a lack of food for the  mantas in that areas.  In the early days they were hunted for their liver oil and skin in California and Australia. Their numbers have been dwindling in recent years. As a result of that, in 2011 mantas became strictly protected in international waters.

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