![]() The fertilized eggs develop within the female's oviduct. The pair remains coupled together for several minutes before going their own way. He inserts his claspers into her cloaca and these form a tube through which the sperm is pumped. 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. When a female is becoming receptive, one or several males may swim along behind her in a "train". Males become sexually mature when their disc width is about 4 m, while females need to be about 5 m wide to breed. It does not rest on the seabed as do many flat fish, as it needs to swim continuously to channel water over its gills for respiration. Such visits occur most frequently at high tide. 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. Earlier assumptions about exclusively filter feeding were based on surface observations. Research published in 2016 proved about 73% of their diet is mesopelagic sources including fish. As many as 50 individual fish may gather at a single, plankton-rich feeding site. 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. 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. An individual manta may eat about 13% of its body weight each week. About 27% of their diet is based on filter feeding, consuming large quantities of zooplankton in the form of shrimp, krill, and planktonic crabs. ![]() Mantas may travel alone or in groups of up to 50 and sometimes associate with other fish species, as well as sea birds and marine mammals. When traveling in deep water, the giant oceanic manta ray swims steadily in a straight line, while further inshore it usually basks or swims idly around. However, there are distinguishing features. ''Mobula birostris'' is similar in appearance to ''Mobula alfredi'' and the two species may be confused as their distribution overlaps. The markings can often be used to recognise individual fish. The ventral surface is white, sometimes with dark spots and blotches. The colouring of the dorsal surface is black, dark brown, or steely blue, sometimes with a few pale spots and usually with a pale edge. The skin is smooth with a scattering of conical and ridge-shaped tubercles. The manta ray does not have a spiny tail as do the closely related devil rays but has a knob-like bulge at the base of its tail. It has a small dorsal fin and the tail is long and whip-like. The eyes and the spiracles are on the side of the head behind the cephalic fins, and the gill slits are on the ventral surface. The teeth are in a band of 18 rows and are restricted to the central part of the lower jaw. 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. It is dorsoventrally flattened and has large, triangular pectoral fins on either side of the disc.Īt the front, it has a pair of cephalic fins which are forward extensions of the pectoral fins. ![]() The giant oceanic manta ray can grow to a disc size of up to 7 m across with a weight of about 3,000 kg but average size commonly observed is 4.5 m.
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