Manta rays

Manta rays are large rays belonging to the genus Mobula. The larger species, M. birostris, reaches 7 m  in width while the smaller, M. alfredi, reaches 5.5 m. 

Classification

Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Order: Myliobatiformes

Family: Myliobatidae

Subfamily: Mobulinae

Genus: Manta , now Mobula

Both have triangular pectoral fins, horn-shaped cephalic (near the head) fins and large, forward-facing mouths. They are classified among the Myliobatiformes (stingrays and relatives) and are placed in the family Myliobatidae (eagle rays).

Manta_birostris-Thailand2

M. birostris image: jon hanson/wikimedia

Manta_ray_from_Yap

M.alfredi with cephalic fins rolled up. image: Bartek.cieslak/wikipedia

Where they are found

Mantas are found in warm temperate, subtropical and tropical waters. Both species are pelagic; M. birostris migrates across open oceans, singly or in groups, while M. alfredi tends to be resident and coastal. 


What they eat

They are filter feeders and eat large quantities of zooplankton, which they swallow with their open mouths as they swim. 

Swimming behavior in mantas differs across habitats: when travelling over deep water, they swim at a constant rate in a straight line, while further inshore they usually bask or swim idly around. Mantas may travel alone or in groups of up to 50. They may associate with other fish species as well as sea birds and marine mammals. 

Giant_Manta_AdF

front facing M. Alfredi image: Arturo de Frias Marques/wikipedia


As filter feeders, manta rays consume large quantities of zooplankton in the form of shrimp, krill and planktonic crabs. An individual manta eats about 13% of its body weight each week. When foraging, it slowly swims around its prey, herding it into a tight "ball" and then speeds through the bunched organisms with a wide-open mouth. If a ball is particularly dense, a manta may somersault through it. While feeding, mantas flatten their cephalic fins to channel food into their mouths and the small particles are collected by the tissue between the gill arches.  


Their life cycle

Gestation lasts over a year and mantas give birth to live pups. Mantas may visit reef cleaning stations for the removal of parasites. Like whales, they breach, but we aren’t quite sure why. 

Mating behaviour

Mating takes place at different times of the year in different parts of the manta's range. Courtship is difficult to observe in this fast-swimming fish. The mating sequence may be triggered by a full moon and seems to be initiated by a male following closely behind a female while she travels at around 10 km/h . He makes repeated efforts to grasp her pectoral fin with his mouth, which may take twenty or thirty minutes. 

Development

The fertilized eggs develop within the female's oviduct. At first they are enclosed in an egg case while the developing embryos absorb the yolk. After hatching, the pups remain in the oviduct and receive additional nutrition from milky secretions

With no umbilical cord or placenta, the unborn pup relies on buccal pumping (breathing with one's cheeks) to obtain oxygen. Brood size is usually one or occasionally two. 

The gestation period is thought to be twelve to thirteen months. When fully developed, the pup resembles a miniature adult and is expelled from the oviduct with no further parental care


Adapted from: Wikipedia contributors. (2018, July 8). Manta ray. In Wikipedia, The Free Encyclopedia. Retrieved 00:27, July 30, 2018, from https://en.wikipedia.org/w/index.php?title=Manta_ray&oldid=849302496