If you were swimming in the warm waters of the Indian Ocean or the Pacific and saw a vast, shadowy shape gliding beneath you, your first reaction might be fear. But if you stayed still, you would discover one of the ocean’s most graceful giants: the manta ray. With wings that can span more than seven metres from tip to tip, mantas are among the largest fish in the sea, yet they are harmless, curious, and deeply fascinating.
Manta rays belong to the same family as stingrays and sharks, but unlike their relatives, they have no stinger and no sharp teeth. Their bodies are shaped like huge diamonds with wing-like fins that flap slowly, giving the impression of a bird flying through water. At the front of their heads are two horn-like fins that funnel tiny plankton into their mouths. These structures are so unusual that sailors in the past thought they looked like the horns of a devil, and mantas were once nicknamed “devilfish”. In truth, they are gentle filter-feeders, eating nothing larger than a microscopic shrimp.
For centuries, little was known about manta rays. They live in tropical and subtropical seas, spending much of their time far from coasts, which made them difficult to study. Some legends painted them as dangerous creatures capable of trapping boats with their wide wings. Fishermen sometimes feared them, imagining that they could drag a person underwater. But in reality, manta rays are shy. They often glide past humans without concern, sometimes even circling divers with a kind of curiosity, as if trying to understand who has entered their world.
DID YOU KNOW?
The largest manta rays can reach a wingspan of over seven metres, wider than many cars are long. Mantas have the largest brain of any fish relative to body size, which may explain their curiosity and social behaviour. Some studies suggest manta rays may recognise themselves in mirrors, a sign of advanced intelligence rarely seen in animals.
Mantas are highly intelligent compared to many other fish. Their brains are the largest of any fish relative to body size, and scientists believe this makes them capable of problem-solving and memory. There is even evidence that mantas may recognise themselves in mirrors, a trait usually seen in animals like dolphins, elephants, and great apes. Their social behaviour also hints at intelligence. Sometimes they gather in groups at cleaning stations—spots on reefs where small fish nibble away parasites from their skin. Watching mantas queue patiently for their turn is like watching visitors at a spa.
There are two main species of manta ray: the reef manta and the giant manta. Reef mantas tend to stay near coastlines, lagoons, and coral reefs, while giant mantas roam the open ocean, travelling long distances. Some giant mantas have been tracked swimming across entire oceans, following the paths of plankton blooms. Despite their size and power, they rely entirely on these tiny drifting organisms for food, filtering thousands of litres of water every day as they swim with mouths wide open.
The beauty of manta rays has made them a favourite among divers and tourists, but sadly, this has not always kept them safe. For many years, mantas were hunted in parts of Asia, where their gill plates were used in traditional medicine. Their slow reproduction makes them especially vulnerable. A female manta may give birth to just one pup every two to five years, after carrying it inside her for more than a year. Unlike many fish that lay eggs, mantas give live birth, and the baby is born as a miniature version of the adult, already capable of swimming on its own. Because they reproduce so slowly, even a small amount of hunting or accidental capture in fishing nets can have a big impact on their populations.
Fortunately, awareness is growing, and many countries now protect mantas. They are listed as vulnerable by the International Union for Conservation of Nature (IUCN), and international trade in manta products is restricted. In places like the Maldives, Indonesia, and Hawaii, manta tourism brings in far more money than hunting ever did.
Today, divers and conservation groups often highlight the contrast between old myths of “devilfish” and the scientific reality of gentle, intelligent creatures. This shift in perception is part of why manta rays are now celebrated as “angels of the ocean.”
High jumpers
Mantas sometimes leap out of the water, somersaulting or slapping the surface—scientists still aren’t sure exactly why.
Cleaning stations
Mantas often gather at reefs where small fish remove parasites, like a natural spa treatment.
Spotted ID cards
Each manta has unique spots on its belly, which scientists use like fingerprints to identify individuals.