The ray adopts a near-stationary position close to the coral surface for several minutes while the cleaner fish consume the attached organisms. Mantas visit cleaning stations on coral reefs for the removal of external parasites. They may also be bitten by cookiecutter sharks, and harbor parasitic copepods. Mantas are themselves preyed upon by large sharks and by killer whales. As many as fifty individual fish may gather at a single, plankton-rich feeding site. 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. If a ball is particularly dense, a manta may somersault through it. 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. An individual manta eats about 13% of its body weight each week.
Manta alfredi at a coral reef cleaning station with fish picking off parasitesĪs filter feeders, manta rays consume large quantities of zooplankton in the form of shrimp, krill and planktonic crabs. alfredi has been shown to dive to depths of over 400 m, while their relative Mobula tarapacana, which has a similar structure, dives to nearly 2000 m the retia mirabilia probably serve to prevent their brains from being chilled during such dives into colder subsurface waters.
Their brains have retia mirabilia which may serve to keep them warm. They have one of the highest brain-to-body mass ratios and the largest brain size of all fish. Mantas track down prey using visual and olfactory senses. The fish's gill arches have pallets of pinkish-brown spongy tissue that collect food particles. The cephalic fins are usually spiralled, but flatten during foraging. The spiracles typical of rays are vestigial, and mantas must swim continuously to keep oxygenated water passing over their gills. Their large mouths are rectangular, and face forward as opposed to other ray and skate species with downward-facing mouths. Mantas move through the water by the wing-like movements of their pectoral fins, which drive water backwards. birostris has a caudal spine near its dorsal fin. birostris also has enlarged teeth on the upper jaw. Both species have small square shaped teeth on the lower jaw but M. alfredi are evenly spaced and lack cusps. The denticles have multiple cusps and overlap in M. alfredi are more rounded, while its ventral spots are located near the posterior end and between the gill slits, and the mouth is white or pale colored. birostris has more angular shoulder markings, larger ventral dark spots on the abdominal region, charcoal-colored ventral outlines on the pectoral fins and a dark colored mouth. The two species of manta differ in color patterns, dermal denticles, and dentition. M.alfredi with cephalic fins rolled up ( Yap, Micronesia)
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