Secrets of the giant manta ray incredible marine life encounters

The Pacific manta ray. These graceful giants were once called devil fish because of their cephalic fins resemblance to the horns of a devil. Now known to be harmless surface dwellers, manta rays prey on nothing larger than plankton and small fish. Occasionally measuring over 20 feet across, the enormous animals are an inspiring sight, gliding through the water like birds in flight. Today we'll journey to a remote group of islands 250 miles southwest of the Baja Peninsula for a remarkable encounter with giant manta rays. We'll examine the fascinating behavior of these fish and other large residents of the island's waters, including humpback whales and bottlenose dolphins. We'll also travel to the Hawaiian islands to witness the feeding habits of mantas at night. And finally, we'll visit British Columbia, Canada and the Vancouver Aquarium to investigate how smart fish really are. Almost 250 miles southwest of the tip of Mexico's Baja Peninsula lies a remote archipelago, the Socorro Islands. Known as Mexico's Galapagos, these uninhabited specks of land are part of the same chain which includes the Galapagos Islands. Lonely outposts in a vast Pacific Ocean, the Socorro Islands are recently active volcanoes that rise thousands of feet from the ocean bottom. Immense fields of lava give evidence of eruptions only 40 years ago. Desolate, battered by ferocious storms and with little fresh water, the Socorro Islands have been spared the effects of a permanent human population. But while there is little sign of life above the surface, the undersea world teems with frenzied activity. Immense schools of fish hover around busy reefs. A jagged, rocky bottom is home to a diverse mosaic of marine life, from spiny lobsters to large moray eels to the masters of camouflage, the strange octopus and the flounder, a highly prized flatfish. What draws marine life to the Socorro Islands is a wealth of food. Plankton-rich water forms the basis of a dynamic, complex food chain. We began our journey in the seaside town of Cabo San Lucas. Cabo is a deep-sea fishing and tourism center and the staging point for our expedition with the Solmar V, a liveaboard diving vessel. Rounding Land's End, the southernmost point of the peninsula, we embarked on a 24-hour, 250-mile journey southwest. Traveling over open ocean, we were luckily spared bad weather and had an uneventful con crossing. The next evening we spotted the first island in the archipelago, San Benedicto. Just above the teeming reefs that surround San Benedicto reign the giants of the Socorro Islands, humpback whales. The coming sunset revealed the first family of whales. From the beginning of January to the end of April, the waters of the archipelago are host to hundreds of humpbacks. They travel thousands of miles on their annual pilgrimage from the North Pacific. The whales spend the winter here mating and giving birth. Along with the Hawaiian Islands, the Socorro Archipelago is home to some of the largest groups of humpbacks in the world. Traveling in small family pods, they can easily be spotted by their telltale waterspouts. The newborns and their parents display many different types of behavior, some of which indicate play. Tail slapping is a favorite activity for both adults and juveniles. Breaching is another form of playful behavior which also may serve to rid the giant mammals of parasites. Other cetaceans, such as dolphins and pilot whales, are year-round residents of the islands. On one of our first dives, we were surprised by the appearance of a large group of bottlenose dolphins. Curious yet cautious, the dolphins easily outmaneuvered slow-moving divers. Frequently found surfing in the bow wake of boats, they do not usually approach humans underwater. This was truly a unique encounter. Dolphins and toothed whales use sound as sonar to visualize the world around them. They produce sound by forcing air between a series of air sacs situated between the lungs and their blowhole. They click, squeak, and groan, and no two sounds are alike. The focus of our trip, and one of the most interesting members of Socorro's undersea family, is the Pacific manta ray. The rays here are the largest and most docile in the world. These enormous fish exhibit very strange behavior. They allow scuba divers to gently touch and interact with them. Some observers speculate that the rays stop for divers because humans appear to be the ultimate giant cleaning fish. One of the reasons this behavior is so unique is that there is no exchange of food. Almost any creature can be trained to accept handouts, but the rays are not fed. Another reason is that the mantas encounter humans for only a few short days in the winter months. They seem to exhibit a distinct capacity for memory, quickly reacting to certain divers they're familiar with. The mantas gracefully glide into position, stop, and invite divers to gently touch their undersides. An extremely abrasive skin texture, like coarse sandpaper, requires a light touch. As the mantas approach you, when we go up to touch them, the mantas really seem to enjoy touching, especially around their belly area, right behind their gills. You can notice this because you'll notice their cephalic fins will actually curl up when you're touching them, and they will also, the wing tips will fold up and they'll actually shake underwater, just as if you were rubbing somebody's or tickling somebody's belly. As a general rule underwater, it's best to maintain a hands-off policy when interacting with marine life. Just observe them. However, this is the one exception to the rule. The mantas seem to actually enjoy the touching underwater and the human contact. Masked and brown boobies joined our boat, and like the mantas, exhibited very tame behavior. Underwater, divers were a curiosity to the friendly birds. One of the most astonishing aspects of the mantas' behavior at Socorro is that they may react to hand signals and body movements. Over the course of a few years, divemasters have developed a simple set of hand signals that the mantas seem to respond to. Veteran diver and trainer Scott Sundby has interacted with the mantas for several years, and was one of the first divers to use hand signals. Approximately three years ago, we started using the hand signals underwater. We noticed that at the cleaning station, the boiler, the fish were maneuvering their fins in a certain way that were calling over the mantas, and the mantas were responding to the signals, and we thought maybe we could use signals of our own. When the diver holds his hand up before approaching the manta, we have to understand that, sure, we see the manta and we presume that the manta sees us, but very likely the manta is also hearing and even feeling the movements of the diver. Manta rays, like sharks, have an ability to sense the electrical potential in our moving muscles, so the fact that these divers who are experienced with mantas are moving very slowly, very smoothly, probably elicits responses that go beyond the seeing capability of the manta. It goes to sensory capabilities that we just don't understand because we haven't got it. Hovering near or on the surface, a manta filters planktonic animals and small fish from the water. Manta rays normally feed at night, and one of the best places to view this behavior is the Big Island of Hawaii. Powerful lights lowered into the water from our dive boat attracted tiny swarming plankton and other minute animals. These, in turn, attract the large mantas that come in for an easy meal. Performing acrobatic loops in front of the light, the mantas efficiently scoop as much food as they can. This spectacle can last all night, with the mantas leaving only after the light is switched off. When they are feeding, their cephalic fins are unfurled and spread apart. The ray swims through the water using the maneuverable fins to help direct food into its cavernous mouth. The manta rays in Hawaii are such regular visitors that over 20 have been identified by their distinctive spot patterns. In the Socorro Islands, familiar mantas are regularly accounted for and logged into a computer file. New animals are entered into the system, along with a drawing or map of the distinctive underside and topside markings. Unique as fingerprints, the markings vary widely. What we're attempting to do here with the computer program is we're trying to identify the mantas. Each manta has a distinguishing marking on the top and or the bottom, and we're trying to input that into the computer so we can identify them both first time that we've seen them and also for each future spotting that we have. Mantas are just one of the 350 species of rays which, along with sharks and skates, are elasmobranch fishes, a group that has evolved independently of the bony fishes. Instead of bone, they have an internal structure made of cartilage. They are not primitive fishes. In fact, elasmobranchs have an acute sense of smell and can sense the electrical fields of other animals, making them extremely good predators. The 350 species of rays include the manta, eagle, bat, cow nose, stingray, and electric ray. Some rays have specialized weapons to deter predators and to stun prey. Electric or torpedo rays can deliver a debilitating shock of electricity as high as 200 volts. Stingrays employ a sharp venomous spine on their tails. They can paralyze an attacking shark and can seriously injure an unwary diver or snorkeler. Mantas can weigh as much as 3,000 pounds. Specimens have been reported at sizes of almost 25 feet across. In Spanish, their name literally means blanket. Atlantic manta rays and their Pacific counterparts were once thought to be separate species. It has since been proven that they are identical animals. Mantas bear live young that are over four feet across. They can be found in all tropical seas except the Mediterranean. In addition to frequenting cleaning stations, manta rays often carry their own parasitic cleaners, remoras. Like magnets, remoras attract sea lice and other pests from the manta. In a strange three-way relationship, both remoras draw parasites from the manta and then eat the pests off each other. They even get a free ride, expending little energy. Remoras are also privy to the smorgasbord of plankton and small animals that the manta feeds on. Absolutely phenomenal. It's one of the best experiences of my life. It's like a ballet dance with a prima ballerina or something. Actually very special. It's a neat experience. Very humble to feel very small. They're large creatures, very graceful. Interesting how they just come up and stop and they want you to go ahead and touch them. Very neat experience. One I'll always remember. Absolutely incredible. Five on that dive. Amazing. Most amazing dive site I've seen. One of the most common misconceptions about fish and invertebrates is that they are not very smart. The manta rays at Socorro are only one of many examples of the remarkable mental abilities of fish. Like more intelligent animals, fish can be trained to accept handouts of food. Even large predators such as sharks can be taught to accept food from humans. Today, one of the most popular attractions in scuba diving are shark feedings. More docile fish like groupers are also frequent attractions for divers. This Nassau grouper named Gilly has been interacting with humans for several years. At the Cod Hole on Australia's Great Barrier Reef, several different species gather together in one place for a feeding. Massive Napoleon wrasse, potato cod, and moray eels aggressively vie for position as tasty morsels of fish are handed out. In the Pacific Northwest, giant wolf eels eagerly anticipate the arrival of human visitors. Supplying them with their favorite food, sea urchins, divers find wolf eels are quite gentle and friendly, despite their fearsome appearance. In Socorro, the mantas are not fed, which makes their behavior all the more unusual. We have found over the years that the mantas have an extraordinary capacity for memory. Not only do they remember us underwater, but they have actually remembered the hand signals each time that we come back. We've gone away for as long as six months, and we've come back, and when we have six divers in the water, the mantas will swim right up to the dive masters first. In order to better understand the intelligence of these marine animals, we visited the renowned Vancouver Aquarium in British Columbia, Canada. We spoke to biologist Dr. Jeff Marley of about the mental capabilities of fish. Fish and invertebrates do have real intelligence, but it's not really the type of intelligence that we understand, because they aren't exactly like us. Because we have eyes and fish have eyes, we assume that when they're looking at us while we look at them, that they're thinking the way that we do. In fact, they have some sensibilities that we just don't comprehend. They have a sensory capability called distant touch, where they can actually feel us moving around in the water. In the case of a shark or a ray, they can actually sense the electricity that our muscles produce when we're moving. So they've got abilities that we don't comprehend, and similarly, they lack the intellectual or rational ability that we have to do things involving reasoning. Some of the things that fish do, we can relate to. A pet fish in some species can recognize its owner and be frightened by strangers. That's something that we can relate to. The way that salmon come off the high seas and find their way to the river they were born in and smell their way home is something that we really don't comprehend, because we can't do that. We just don't have a very good sense of smell compared to most animals. One of the North Pacific fishes that divers are familiar with as having a type of intelligence is the wolf eel. It's one of these types of fish that gets friendly with divers. They live in a den for a long period of time. They're long-lived like we are, and so divers get to know individual wolf eels. And in the case of the wolf eels we'll see here at the aquarium, where they've been fed by hand all their lives, they're extremely diver-friendly to the point of looking like they're mobbing the diver. They know they'll get a meal. So it's just a case of a bit of learning, a good memory, good ability to recognize things, animals, in their environment. When we talk about fish and their intelligence, we do tend to think about our own intelligence. We have a good memory. We have a terrific ability to learn. So when we see fish showing an ability to learn or to remember, we tend to think, aha, they're much like we are. We have to remember that there are fish that are reacting in tremendous detail to everything around them, who aren't necessarily doing much of any remembering. In the case of schooling fishes, for example, it's all based on instinct. Fish actually have much more reliance on instinct than we do, even though they can layer on top of their instincts their ability to recognize experiences that they've had before. People ask questions not only about learning in fish, but about the way fish feel. Can a fish feel that it's being hurt? Well, yes and no. A fish can feel when a hook goes in its mouth, and it certainly reacts to it. And it can feel when you pull the hook out. But after it's been wounded, can it dwell on it? Can it think, ouch, boy, that's killing me? No, they don't have that part of their brain that we have to dwell on things, to rationally contemplate what has happened to us. Many species of fish display hunting techniques, camouflage abilities, and mating rituals thought to be the exclusive behavior of more advanced creatures. With our marine resources being depleted at an unprecedented rate, it may be too late to fully study and comprehend the behavior and intelligence of marine animals. Perhaps if we thought of fish and invertebrates as beings capable of thought and feeling, maybe we wouldn't be so quick to destroy them. In Socorro, graceful manta rays are now protected from fishing. In a rare environmental success story, a passing sailor captured on video the slaughter of several mantas. After turning the video over to authorities, the government acted quickly, banning all commercial fishing in the archipelago. In other areas of the world, many species of fish, especially those that are commercially harvested, are on the verge of extinction. The future is uncertain for these misunderstood residents of our last frontier. If we could really appreciate the different types of intelligence that fish have and understand the way that they behave, the complexity of their abilities, maybe we would think more seriously about life in the oceans. The fact is that since we don't live under the sea and we don't see under the ocean surface very often, we don't think quite as seriously about marine life. And perhaps that's why we really aren't showing such great intelligence in the way we deal with life in the Maybe if we understood marine life better, we wouldn't be overexploiting the fish stocks in the world's oceans.