Happy World Manta Day! Every year, we celebrate these gorgeous, magical underwater marvels on the 17th of September. It’s a day to wonder about the lives of these glorious specimens of evolution, and think of ways that we can help in the conservation, protection, and propagation of the species. Manta rays and devil rays are found in abundance in the Maldivian waters. In fact, the Maldives is popularly home to the largest congregations of Mantas found anywhere in the world. Our island nation is also home to several conservation projects for these majestic underwater creatures, most notably Maldivian Manta Ray Project (MMRP), the founding project of UK registered charity ‘Manta Trust’. Manta Trust has been working since 2011 to coordinate global mobulid research, conservation efforts and even lets you ‘adopt’ a manta! Over the last 15 years, the MMRP has identified over 5,000 individual manta rays in their comprehensive database.
While conservation and protection is what today is also about, we also want to give you some fun facts about Manta rays and devil rays in the Maldives. Here are some quick facts about Manta Rays that you may not have known.
1. Mantas have seriously huge and impressive brains!
Mantas are incredibly smart and have one of the largest brain-to-body ratios of any fish. They were actually the first fish in the world to pass the ‘mirror’ test. Two mantas were shown a mirror and they didn’t think the reflections were other mantas, instead recognising their reflections as reflections. In fact, one of the mantas actually watched itself blowing bubbles for a time, and the Mantas twisted themselves this way and that curiously! Mantas also have highly developed long-term memory, as evidenced by the fact that studies have also shown that manta rays are able to create mental maps of their environment through smell and visual cues.
2. Mantas can get so so so big
Manta Rays are known as some of the largest megafauna, they can grow to weigh as much as 1,350 kg with average 23ft wingspans. However, the Giant Oceanic Mantas are different from reef mantas found in the Maldives waters. The largest wingspan for a Manta ever recorded was 30ft. Reef mantas, more commonly found in temperate waters like the Maldives, can grow up to 16ft but the average size commonly observed is about 11ft.
3. Manta can never stop swimming
Manta rays belong to the group of fish who have to keep moving in order to keep breathing, so you will never find a manta ray that isn’t swimming. The motion of swimming is what gets oxygen-rich water pushed through their gills and keeps them breathing. Sharks are similar to this, in that they can never stop moving throughout their life. Mantas often undulate with their wings under the water too, staying in one spot but continuing to move all the same so they can get their oxygen.
They’re extremely good at deep diving too. Mantas can easily dive upto 1km deep with no issues.
4. They try to fly?
We know now that they can dive, but they also try to fly sometimes. Or atleast, that is how it appears because Mantas are also known to sometimes leap up out of the water. Scientists don’t know exactly why they do this, but the sight of hundreds of manta rays leaping out of the water like a pod of dolphins is truly a sight to behold. It is speculated that this may be a mating ritual, with the males showing off to females, or that they are cleaning themselves of parasites, communicating or even that they are simply having fun jumping around. After all, mantas are, like we said, highly intelligent, curious, and very much interested in play.
5. Suspiciously similar to kites
Have you ever seen a Manta Ray leaping up out of the water, as though trying to fly like a kite? In the Maldives, the collective name for underwater rays is ‘Madi’ which is the same word we use for kites. Could it be that ancient Maldivians saw them leaping out into the air and named them after kites?
6. Mantas have their own friend groups
Manta Rays not only make friends with humans due to their curious nature, but they also form friendships with each other. Mantas, mostly females, are known to make friend groups that they travel together with to cleaning stations and feeding stations. Strangely, they usually have two different friend groups; one to go grooming with, and another for feedings. Males love to hang out in feeding stations while females, more likely to create social structures, prefer cleaning stations. All female groups are more likely to last for longer, and the ‘feeding group’ is a separate group filled with males, females, and young ones.
7. Mantas love being pampered!
If you didn’t know before, Mantas are big on grooming. They love getting full body cleanings. They will often go to the same cleaning stations to give themselves over to the cleaner wrasse, sergeant majors, and copepods for hours to get all the parasites, dirt and other things off their bodies. Mantas will return to their favourite cleaning stations over and over again for years on end. They are also very well-behaved as they will make a little civilised queue and wait patiently for their turn at the grooming stations.
8. Mantas make mating trains
Manta Rays have an average lifespan of some 50 years, and the females are ready to start reproducing at age 15. When females are ready to reproduce, upto 30 hopeful males will often line up around her, making a sort of ‘mating train’ that’s very fun to watch as they all try to impress her and get ahead of the other males. Female mantas remain pregnant for over a year, and give birth to just one pup at a time (sometimes twins!), and they’re known to reproduce once every two or three years.
9. Mantas are fish but give live birth like mammals!
It is very strange that they give birth to live pups although the pup incubates inside its body within a shell, which then cracks open inside and the pup comes out alive. They sometimes give birth to the ‘baby burrito ray’ out in the middle of the act of leaping up out of the water! Pups are expected to fend for themselves from the moment of birth as female mantas do not spend any time rearing their young.
10. Don’t touch that pup, or it’s mamma
Did we also mention, manta pups look exactly like adult mantas when born, with a wingspan of about 5ft on average at birth. They are exceptionally cute, however, never ever touch a manta ray, not a pup or an adult. Mantas have a special mucus membrane all over their bodies that protect them from bacteria. Human touch can remove this film from their bodies, leading to illness, infections and possibly even death.
11. Mantas sometimes go into a cyclone feeding frenzy!
Manta rays are filter feeders; they swim around getting plankton and other tiny delicacies into their gill rakers and gill arches in their wide, open mouths. They can’t really eat any fish, and would probably spit it out if it got into their giant mouths! When there is an especially large amount of plankton around, the Mantas will go into what is known as a cyclone feeding frenzy! Hanifaru Bay is one of those rare places in the world where this occurs on a regular frequency.
“From May through November, when the lunar tide pushes against the Indian Ocean's southwestern monsoon current, a suction effect pulls tropical krill and other plankton from deep water up to the surface. The current sweeps the krill into the cul-de-sac of Hanifaru Bay. If the krill stayed at the surface, they'd wash over the bay's coral walls and out to the safety of the open sea. But they can't. Instinct forces them to dive away from daylight. When they do, they get trapped deep in the bowl. In just a few hours a massive concentration of plankton builds up, a swarm so thick it turns the water cloudy.” - National Geographic
This delicious bowl of plankton is exactly what drives the mantas into their feeding frenzy. The mantas swirl and dance around trying to get as much plankton and krill as they can into their wide gaping mouths. Manta feeding frenzies are very well-documented but astonishing to watch all the same. One fun part about watching the hundreds of plankton-crazed manta rays swirling through Hanifaru Bay is to keep an eye out for Whale Sharks, who also like to join in on the feast in the dozens.