© Guy Stevens
I am gazing in wonder at a flying carpet. Underwater. It's a manta ray, winging along with the greatest of ease, keeping an eye on me. And I say "eye" singular because each eye is positioned to either side of its front lobes, spaced well apart.
Correction. Make that two flying carpets. Right over the top of the first one comes another manta, flying straight toward me. I wanted to get close to mantas, but not this close. The creature has a huge wingspan—some 500 kilograms of flying carpet is set on a head-on collision course—and I have nowhere to go. I am in panic mode. But at the last moment, it nose-dives into the depths. Is this the manta ray's idea of a joke?
The giants wheel back—both of them. There's no doubt in my mind now that they are eyeballing me with curiosity. They know exactly where I am, and are avoiding any collision course, despite a three-meter wingspan. They show off with a stunning underwater ballet, winging along effortlessly, performing acrobatic turns. This undulating "choreography" goes on for several minutes—the maximum time that I can breath-hold underwater—but seems to last much longer. The mantas have let me into their world for an instant, an instant that is truly magical. A world of underwater acrobats.
More marine encounters over the course of the next week convince me that these rays are truly bizarre creatures, charismatic, graceful, and gentle despite their size.
I am on a vessel dedicated to tracking them: the Manta Trust research boat, patrolling Baa Atoll in the Maldives. In 2011, Baa Atoll was designated a UNESCO World Biosphere Reserve. This was largely due to its unique reef manta population, plus the efforts of Guy Stevens, who heads the research project here. The Maldives hosts the world's largest known population of reef mantas, estimated at over 6,000 resident rays.
Being on board this converted fishing vessel offers a glimpse into another world: the world of marine researchers, patiently probing the mysteries of these enigmatic creatures. How long do mantas live? How often do they reproduce? How do they avoid predators? Project manager Niv Froman is scanning the waters from the top deck, checking for mantas cruising near the surface, chasing plankton. Making spotting easy is a large ray that goes airborne—flying through the air near the boat in a spectacular display of breaching. Two volunteer research assistants get ready to freedive and ID the acrobatic ray by photographing the distinctive spot-patterns on its underside--a pattern that never changes. Once in the research database, mantas are given nicknames like Rocket, Flappy Jack, and Bubbles (who likes to be tickled by bubbles from divers).
According to Guy Stevens, these gentle giants have a high tolerance for "bubble creatures" entering their marine domain. The bottlenosed dolphins we see playing in the bows of the boat will dive down to lose any snorkelers who enter the water close by. By contrast, mantas will actively interact with divers and snorkelers, most likely out of curiosity. In the early days of scuba-diving—back in the 1970s—mantas were real flying carpets: divers were known to hitch a ride by holding onto one.
Guy tells me these rays have the largest brain to body weight ratio of any living fish. Does that indicate higher intelligence? Quite possibly, says Guy, if problem-solving is a parameter. Mantas are among the very few marine creatures that will actually seek out humans to solve problems, such as being half-strangled by a fishing net. A man-made problem requires a man-made solution. Numerous times, Guy says, he has been approached by mantas tangled with netting. After the hapless creature is cut loose, it often follows him for some time in an apparent show of gratitude.
Mantas never sleep: from the moment they're born, they're on the move. How can they operate like this? "Well," says Stevens, "it's not sleep as we know it, but mantas have relaxation modes, rather like auto-pilot or cruise control, where they glide using very little energy." Relaxation time includes visiting a "cleaning station". About 50 cleaning stations have been discovered around the Maldives. At these sites, mantas wait patiently in turn to hover in over a reef and have parasites removed by cleaner-fish. Rather like going to a car wash or the hairdresser's. Divers visit these sites too, hoping to see a manta line-up.
But the ultimate place to see line-ups is Hanifaru Bay. If conditions are ideal here, mantas aggregate to gorge on swarms of microscopic plankton trapped in the bay. At Hanifaru Bay, Stevens says researchers have counted aggregations of 50 mantas (and once counted 240 of them total) engaged in a feeding frenzy, gliding along with sometimes two or three stacked on top of each other. Other times, they curl up and perform loop-the-loop barreling maneuvers to gobble up more plankton.
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