 Man is well-designed for his natural habitat, the land, but he's never been happy confined to it. The horse got his feet off the ground. Then man invented the engine and really got going on land, sea, and finally in the air, slowly at first, then faster and faster until he flew right out of this world. The water turned out to be the toughest for man to conquer. Beneath the ocean, there is still a vast unexplored frontier. The deep sea bottom is a virgin mass of land, three times the size of all the continents combined. Man walks on the sands of earth and the dust of the moon, but no man has ever walked on the floor of the deep sea. Only in a thin layer at the top, the first few hundred feet, can man move about freely in the sea. Below this, the ocean is cold, dark, and deep. To venture here, we must be encased in a massively structured, cumbersome vehicle that will protect us from crushing pressure. We're terribly handicapped. Our hearing and eyesight are practically useless in deep water. And we can't tell up from down in the darkness. We have to carry our own life support system, and all the while our body heat is leaking away. So, here we are, able only to move slowly and clumsily through the sea with little or no benefit of our eyes, ears, nose, or sense of balance, and threatened by the cold and the pressure and endangered by fast-moving sea creatures we cannot see or hear approaching. We can't even surface quickly to escape danger without risking a possible fatal attack of the bends. The deep sea is truly the most hostile environment that man has ever attempted to conquer. Man, an air-breathing animal, is simply not designed for survival in the deep sea. But we aren't really discouraged by all these problems, for we know it can be done. How? Well, because man is not the first air-breathing land mammal to attempt living in the sea. A long time ago, another land-based air-breathing mammal moved into the sea and conquered it. He's the small whale we call the dolphin, and he's survived and flourished in the oceans for 60 million years. So for the past eight years, we've been conducting a scientific investigation of this sea mammal that we so admire and envy. The dolphin was recruited to help us learn how man can function better under the sea, and we're learning a lot. One dolphin, perhaps more than any other, has helped us break through some of the barriers to new knowledge of our sea environment. His name is Tuffy. This film is a report on some of the things we've learned with the invaluable help of Tuffy and his friends. Recruiting dolphins for our scientific investigative programs has some similarities to a cattle roundup. In shallow water, dolphins can be caught by encircling them with a long net. But in deep water, we make use of the fact that dolphins love to hitch a free ride on the bow wave of a boat going in their direction. And this sea-going cowboy is literally going to lasso one of these hitchhikers when he surfaces to breathe. It's not easy, either. Lassoing one or two dolphins and getting them aboard is considered a good day's work. The lasso, actually a hoop with a long net attached, is slipped over the head of the swimming dolphin. The net forms a bag over the forward part of the reluctant recruit. It's placed on a foam rubber mattress and covered with a wet cloth. On the way back to port, water will frequently be sprayed over him to keep his skin moist and help keep him cool. Dolphins don't have sweat glands. Once ashore, the new recruit is hurried to a filtered saltwater pool and work begins on getting him adjusted to a much altered environment. Compared with other wild animals in captivity, dolphins rarely bite. This dolphin was an exception. He didn't care for his new environment at all. In fact, he was so belligerent, one of the scientists said, I think maybe we have the world's first man-eating dolphin on our hands. He soon acquired the name Tough Guy, later shortened to Tuffy, and he wanted nothing to do with people. After a while, our trainers, tired of dodging those dozens of sharp teeth that can slice a fish in half, temporarily gave up on Tuffy and concentrated on the other dolphins in the program. Most of the other dolphins had adjusted to their new surroundings quickly and were responding nicely to their trainers. Obviously, if we were to learn anything from working with dolphins, some form of communication between man and dolphin had to be established, and you've probably heard or read a lot of wild speculation about dolphins being capable of talking with people. It's true that dolphins have been trained to emit sounds that imitate human speech, but there's no acceptable scientific evidence that these sounds mean anything to the dolphin remotely like what they mean to people. And like every other animal, dolphins communicate with each other. But again, there is no conclusive experimental evidence to indicate they communicate at anything like the conceptual level of human speech or exchange abstract ideas. Since we are interested in learning more about the dolphin's environment, the sea, and not in teaching him about ours, our need to communicate with the dolphin is limited to conveying instructions to him to perform specific tasks under controlled conditions that permit us to observe and record the results. To accomplish this, our trainers use basically the same communication techniques that animal behavior experts have had great success with in training other wild and domestic animals. Governor John Hall explains how it's done. When you want to communicate to a dolphin the behavior he is to perform, you break down the behavior into the smallest steps. For example, some of the behaviors the dolphins perform require him to carry a package or tow a line. The package or line is attached to a ring like this one, which fits over the dolphin's rostrum. First we teach him to pick up and carry the ring on signal. I start by placing the ring against his rostrum. Then I blow the whistle and give him a reward. The whistle which I blow at the precise moment he performs the behavior is my signal to him that he has performed correctly and will be rewarded. Now that I've done that a few times, I'll put the ring over his rostrum, take my hand off it for a second, then reach back and take the ring off, blowing the whistle as I do so, and rewarding him. I'll repeat this a number of times. I'm going to put the ring over his rostrum, move my hand a couple of inches away, and not reach for the ring to remove it. The animal should generalize now and bring the ring to me on his own. The animal appears to understand the basic idea now. Next time I'll move my hand a few inches further away and he'll move the ring over to it. After a while I stop putting it on his rostrum and just lay it in the water beside him. Finally after a few hours practice I can toss the ring anywhere in the pool and he'll immediately go get it and return it to me. This is an oceanographic instrument package that is lowered to collect data on the ocean bottom. It can be recovered from the seabird by a dolphin that's trained to retrieve the ring. Let's see if he can do it correctly. None of the trainers made any progress with Tuffy until Debbie Duffield, a college student in animal husbandry working on a summer job with our researchers, was given a chance to see what she could do. Debbie took a few bumps and bites but she was persistent. Gradually Tuffy began to respond to her special attention. Because of the fine friendship that developed, Tuffy very rapidly began to learn the tasks Debbie assigned him. By the end of summer, when Debbie returned to school, Tuffy was well on his way to the head of the class and he continued to work well with his new trainers. One of the early program objectives of our research was to find out if dolphins could be controlled in the open sea, where if they chose they could just swim off and never return. After months of work, our scientists turned Tuffy loose in the sea and held their breath. But when they sounded the return to the trainer signal, he came back to the boat like a flash. This marked a critical milestone in our program for it meant we would be able to control and work with the dolphin in his natural environment, the sea, not just in a tank. Since we use food as a performance incentive to the dolphin, our scientists were worried about how the abundance of food available all around him in the open sea would affect his behavior. Tuffy just ignored all the tempting ordoers and stuck to his tasks, although some of our other dolphins couldn't resist the temptation to occasionally chase down a snack. Life for the dolphins working in our research program is pretty soft. They live in pools of clean, filtered seawater, get fed 15 to 20 pounds of fresh fish daily, and get their vitamins in the very best of medical care. Dr. Sam Ridgway, our distinguished research veterinarian, gives this dolphin named Cyclops her weekly physical examination. Cyclops, or Psi, has worked with our researchers for almost eight years and wouldn't be alive today except for the close medical watch kept over all the dolphins. Three years ago, Psi developed seriously infected ovaries, a condition that would have been fatal to a wild dolphin. But Dr. Ridgway, using an anesthetic procedure he perfected, was able to perform a surgical hysterectomy on Cyclops, the first successful major surgery in history on a marine mammal. Since then, Dr. Ridgway has performed successful surgery on a number of other dolphins as well as on other marine mammals in the program, such as this sea lion. There are a lot of reasons the Navy is studying dolphins and other marine mammals, but the dolphin sonar and directional hearing are among the most important ones. Pioneer work in identifying the range of the dolphin's hearing was carried out by Dr. Scott Johnson. Marine zoologist William Evans has conducted important research in identifying the frequencies and patterns of the dolphin's pulses. Dr. Johnson discovered that the dolphin has a remarkable hearing range, ten times as wide as man's hearing. His sonar is even more remarkable. This dolphin named Salty repeatedly recovered a vitamin capsule tossed in her pool and did it blindfolded, returning it each time to Dr. Johnson. Scott Johnson and Bill Evans, along with the Navy sonar experts, are studying the dolphin's pulse system for ideas that may be applicable to Navy sonar equipment. When a man swimming underwater hears a sound, he has difficulty telling what direction it's coming from. A dolphin can. And this precise directional hearing ability is highly useful to him and to us. When a need arose to quickly train a dolphin to work with aquanauts who would live under the sea for 30 days in the C-Lab II experiment, the immediate choice for the job was toughy. Scientists working with toughy had become more and more impressed by his amazingly quick responses. He was learning new tasks in as little as 10 minutes and easily adjusted to new situations, hardly anything scared him. He learned his tasks so well, in fact, that he would become angry at his trainers if they failed to carry out their end of things exactly right every time. While the aquanauts of C-Lab II were living 200 feet below the surface of the sea, toughy carried tools down to them and brought back mail to the surface. Toughy was also on standby duty to go to the rescue of any aquanaut who might find himself lost in the black water away from his sea floor habitat. In this drill, a diver simulating a lost aquanaut sounds a buzzer he carries. Toughy up on the surface hears the alarm and goes to the rescue. Diving down to the C-Lab habitat, he picks up a line and carries it out to the lost aquanaut, halving in on him with his directional hearing response to the buzzer being sounded and with his sonar. The aquanaut takes the line from toughy and follows it back to the safety of the habitat as the line reels itself in. Toughy goes back topside to be rewarded for his good work. When you descend into the sea, the weight of the tons of water above you increases the water pressure at the rate of about one half pound per square inch for each foot you descend. Man's body isn't designed to absorb the tremendous pressures that build up as we go deeply in the sea. This pressure causes increased amounts of nitrogen gas to dissolve in our bloodstream and body tissues. Unless a diver who goes deep is very slowly brought back to the surface, rapid decompression causes the dissolved nitrogen gas in his bloodstream and tissues to form gas bubbles, just as bubbles appear in a carbonated drink when you remove the cap and reduce the pressure. These bubbles can form in the blood and body tissues, including the brain, causing nitrogen narcosis and the bands, which at best is severely painful and requires the diver to spend hours in a recompression chamber. At worst it can be fatal. All whales, including dolphins, can dive to great depths with no visible ill effects. While he is not breathing underwater as a human diver is, the dolphin does carry down a lung full of air. Why doesn't the nitrogen in this air dissolve in his blood and tissues when he rapidly decompresses and cause the bands, rapture of the deep, aeroembolism and other conditions that affect human divers? Working with Tuffy, Dr. Ridgway set up an experiment to find out. At the time these tests were conducted, no one really knew to what depth the dolphin could dive. Dr. Ridgway set out to obtain scientific evidence of the maximum depth that Tuffy could dive, to obtain breath samples from Tuffy before he returned to the surface and to photograph by a remotely operated camera the physical appearance of the dolphin at great depths. Now after several months of work, Tuffy is diving in the 800 foot range. No one knew a bottlenose dolphin could go this deep. Today, Tuffy will try for 975 feet. Several pieces of apparatus had to be built to collect data on Tuffy's dives. The heavy cable being lowered has a protected plunger switch that Tuffy must press. His pressing this switch will turn off the buzzer, fire the flash gun and operate the camera being lowered. Before reaching the surface after his dive, Tuffy has been trained to blow his breath into this funnel, which traps a sample of it in the attached container. Taking several quick breaths, Tuffy heads downward. The push button switch at the end of the cable is his target. Far above, trainer Bill Sconce sees the light go out, indicating Tuffy has shut off the buzzer some 975 feet below. Tuffy stops off before reaching the surface and on signal blows his breath into a sample collector for Dr. Ridgway to analyze. One mystery that Dr. Ridgway is trying to solve is why Tuffy's chest isn't crushed at the awesome pressure of 975 feet. And even if he can survive it, which he obviously does, why doesn't he get nitrogen dissolved in his bloodstream and tissues? Analyzing Tuffy's exhaled breath shows the oxygen carbon dioxide changes that occurred during the dive. How do they do it? Well, the mystery is solved. Here's a photograph of Tuffy as he looks normally. And here's a photograph of Tuffy at 975 feet. As you can see, his entire lung area is totally collapsed by the water pressure. His chest is designed to be compressible. The dolphin's body is actually so flexible he can undergo this kind of a pressure squeeze without injury. And why doesn't he get the bends? Well, when his chest and lungs collapse, it blocks the normal process of gas transferring from his lungs to his bloodstream. So, since the air gases in his lungs can't enter his bloodstream, he doesn't get any increase in the nitrogen in his blood and tissues. Although he decompresses very rapidly by swimming back to the surface, there is no dissolved nitrogen in his blood and tissues to form gas bubbles. Consequently, no nitrogen bubbles, no bends. Some of Tuffy's huge cousins, like the sperm whale, can dive to over 3,000 feet and stay down for more than an hour. Apparently, their systems function the same way. Other sea mammals who are deep divers, such as the sea lion and the seal, obviously are adapted to withstand the effects of deep diving. Well, during the first eight years that Tuffy and his friends worked with our scientists, what have they taught us? How have we benefited? First, the dolphin has become a domesticated animal. He has exceptional capabilities in the sea, especially in situations where man is least effective. He was proved that dolphins could be released into the open sea and would return when called. He has given us new approaches on the use of sonar that will result in the sea becoming a little less opaque to man. The dolphin sonar also has possible practical application as an aid to the blind. And he's taught us how he can dive down to the crushing pressures of the deep sea without harm. Knowledge that will be helpful as we seek ways for man to move deeper into the sea. As we gain knowledge of how his directional hearing works in water, we may be able to utilize this knowledge to improve man's directional hearing underwater. From the exhaustive investigation of his physiology and development of new methods of treatment of the dolphin's diseases, we have gained new knowledge that not only will help preserve the health of our animals, but will also be a direct benefit to man. Encouraged by our success with the dolphin, our scientists are broadening their studies of sea mammals and birds, as each has much to contribute. We're studying the killer whale, who appears to be just as friendly and trainable as the dolphin, the deep diving sea lion, and the large stellar sea lion. From the workhorse of our accomplishments, our number one sea teacher has been this 270 pound bottle nose dolphin from the Gulf of Mexico. The knowledge gained from him helped our scientists train the team of dolphins working with us today. In the spring of 1970, Tuffy died of a rare bacterial infection, one never encountered in a dolphin before. Even though Tuffy is gone, the work continues with other members of the dolphin team, who recently were joined by a new little fellow. Researchers in the future will build on his contribution as they probe ever further into one of man's most challenging frontiers, the deep sea.