Manta Rays: Gentle Giants Explained

Manta Ray Facts
An oceanic manta (Manta birostris)

1)  THERE ARE TWO SPECIES OF MANTA RAYS – OCEAN MANTAS (MANTA BIROSTRIS) AND REEF MANTAS (MANTA ALFREDI). M. birostris is also sometimes known by the names giant ocean manta and Atlantic giant manta. Mantas are the largest members of the ray family and among the largest fishes in the sea.

2) Oceanic mantas are found worldwide, often reported as swimming great distances across oceans. They generally prefer tropical and subtropical waters.

3) Reef mantas are found largely in Indo-Pacific habitats, including Hawaii, Australia, Micronesia, Polynesia, Indonesia and the Maldives. They generally prefer shallower, coastal waters. They’re also more likely to limit themselves to specific habitats.

4) Both species are plankton feeders, with forward-facing mouths that sweep in zooplankton like shrimp, krill, copepods, worms, fish larvae and small fish. Unique gill rakers filter these foods from the water.


5) Both feature the ray architecture of broad flattened bodies, with wide pectoral fins that they “flap” like wings to propel themselves, and long tails. The name “manta” is taken from the Spanish word for blanket or cloak, reflecting their broad bodies.

6) And both are equipped with horn-shaped cephalic fins that project ahead of their mouths to help funnel plankton-laden water into their mouths. The rays keep them rolled like spirals when they are swimming and flattened when channeling plankton-laden water. These horn-like fins account for mantas’ sometimes nickname of “devil ray.”

7) Relative to their body sizes, mantas have the largest brains of any fish. The brains of much larger whale sharks are only one-third the size of mantas’ brains. Perhaps that explains mantas’ curiosity around divers.

8) Unlike other rays, they lack stingers and are unthreatening to humans (sadly, the same is not true in reverse).

9) Oceanic manta rays are the larger of the two species, with adults typically featuring “wingspans” of up to 23 feet. Individuals as large as 30 feet have been recorded.

Manta Ray Facts
A reef manta (Manta alfredi)

10) Reef mantas can grow to a wingspan of 15 ft/5 m but are typically more in the range of 11 ft/3 m in size.

11) Both oceanic and reef mantas have dark upper (dorsal) sides and light-colored lower (ventral) surfaces with patterns of spots and blotches as specific to each animal as fingerprints. Flower Garden Banks National Marine Sanctuary maintains a catalog of dozens of mantas, identified by their markings.

12) Like dolphins, mantas sometimes do acrobatic leaps out of the water. The reasons are not clear. Marine biologists speculate their jumping may be part of mating dances, to help clean parasites, or just for fun.

13) Yes, manta rays visit cleaning stations to have dead skin and parasites removed by small fish.

14) Manta rays are ovoviviparous; they give birth to live pups. Males can be distinguished from females of the pair of claspers located near the base of the tail.


15) Like sharks and other rays, mantas are cartilaginous fish. Their skeletons are composed of cartilage, not the calcium material of bony fish. Like some sharks, they need to swim continuously to pump oxygen-rich water through their gills.

16) Mantas are classified in the same family as eagle rays. Whereas eagle rays have their mouths on their ventral) sides, mantas have evolved to have forward-facing mouths designed to sweep in plankton-laden water.

17) Mantas are in the same subfamily as mobula, which resemble manta rays but are smaller with somewhat differing mouth anatomy. Oceanic and reef mantas are separate species from the nine species of mobula.

18) Mantas face significant threats from such factors as pollution, overfishing, entanglement in fishing nets and pollution. Manta meat is considered a delicacy in some cultures, and their gill rakers are sought as an exotic substance for use in Chinese medicine.

19) With slow reproduction rates, both species of manta rays are listed as“Vulnerable” by the International Union for Conservation of Nature.

20) Recent research has found that mantas’ gill raker system is unique among filterers and may help scientists develop technology for such uses as filtering out tiny plastic particles that represent an environmental hazard.

PRINCIPAL SOURCES: Manta birostris, Florida Museum, University of Florida; “Research raises possibility that Flower Garden Banks National Marine Sanctuary is part of manta ray nursery,” NOAA: “Nursery For Giant Manta Rays Discovered In Gulf Of Mexico,” NPR; “Rare Manta Ray Nursery Discovered,” National Geographic; “Rock-a-bye manta ray, in the ocean: The first manta ray nursery is found,” Durham Herald-Sun; “Research raises possibility that Flower Garden Banks National Marine Sanctuary is part of manta ray nursery,” NOAA; “Manta Catalog,” Flower Garden Banks National Marine Sanctuary; Manta Ray, Reef Manta Ray,; “Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico,” (Abstract) Marine Biology.