These can be rolled up in a spiral for swimming or can be flared out to channel water into the large, forward-pointing, rectangular mouth when the animal is feeding.

While for the oceanic manta ray, the dorsal surface is deep dark and the two white areas are well marked without gradient effect.

[2] It is an ocean-going species and spends most of its life far from land, travelling with the currents and migrating to areas where upwellings of nutrient-rich water increase the availability of zooplankton.

[citation needed] Since 2018 Ꮇ. birostris has been exhibited at Nausicaä Centre National de la Mer in France and Okinawa Churaumi Aquarium in Japan.

[19] When foraging, it usually swims slowly around its prey, herding the planktonic creatures into a tight group before speeding through the bunched-up organisms with its mouth open wide.

[18] While feeding, the cephalic fins are spread to channel the prey into its mouth and the small particles are sifted from the water by the tissue between the gill arches.

[20] The giant oceanic manta ray sometimes visits a cleaning station on a coral reef, where it adopts a near-stationary position for several minutes while cleaner fish consume bits of loose skin and external parasites.

During copulation, one of the males grips the female's pectoral fin with his teeth and they continue to swim with their ventral surfaces in contact.

Long gestation periods and slow reproduction rates make this species highly vulnerable to shifts in population.

Nonlethal shark bites are very common occurrences, with a vast majority of adult individuals bearing the scars of at least one attack.

[29] Because M. birostris feeds in shallow waters, there is a higher risk of them getting caught in fishing equipment, especially in surface drift gillnets and bottom set nets.

[30] Whatever the type of fishing (artisanal, targeted or bycatch), the impact on a population which has a low fecundity rate, a long gestation period with mainly a single pup at a time, and a late sexual maturity can only be seriously detrimental to a species that cannot compensate for the losses over several decades.

[29] Since the 1970s,[31] fishing for manta rays has been significantly boosted by the price of their gill rakers on the traditional Chinese medicine market.

A 2019 study in Indonesia's Coral Triangle was performed to determine if the filter-feeding megafauna of the area were accidentally ingesting microplastics, which can be eaten by filter-feeders either directly (by ingesting layers of plastic polymers that float on the surface of the water in feeding areas) or indirectly (by eating plankton that previously ate microplastics).

The results of the study provided ample evidence that filter feeders, such as oceanic manta rays, that lived in the area were regularly consuming microplastics.

Though it was also proven via stool samples that some of the plastic simply passed through the digestive systems of manta rays, the discovery is a concern because microplastics create sinks for persistent organic pollutants like dichloro-diphenyl-trichloroethanes (DDTs) and polycyclic aromatic hydrocarbons (PAHs).

There has been at least one study that has shown how heavy metals such as arsenic, cadmium, and mercury can be introduced to the marine environment via pollution and can travel up the trophic chain.

For example, there was a study in Ghana that involved the testing of tissue samples from six M. birostris carcasses; all of them showed evidence of high concentrations of arsenic and mercury (about 0.155–2.321 μg/g and 0.001–0.006 μg/g respectively).

While the sample size was not the most ideal, it is a first step towards further understanding the true amount of bioaccumulation that M. birostris undergoes due to human pollution.