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The story of a dolphin / Emily Anthis

A dolphin named Winter lost her tail after being caught in a crab trap. So scientists built her a new tail

Winter the dolphin. Credit: Courtesy of Hangar Ltd
Winter the dolphin. Credit: Courtesy of Hangar Ltd

When Winter the dolphin was a few months old, in December 2005, she swam alongside her mother in Mosquito Lagoon, which stretches along the Atlantic coast of central Florida. Unfortunately for her, Winter was caught in a crab trap. A one-eyed fisherman spotted her trying to escape from the trap and called a wildlife rescue team for help. Rescue team volunteers gently placed the common dolphin on a stretcher, carried it out of the water and drove it to the other side of Florida, to the Clearwater Marine Aquarium.

Winter arrived in critical condition: exhausted, suffering from dehydration and covered in cuts and bruises. She could barely swim. The aquarium trainers stood around her in the pool and held her little body in the water. No one knew if she would survive the night. But the little dolphin proved to be a true survivor and passed the first night, and the one after it, safely.

Slowly, thanks to the staff who fed her from a bottle as a baby and watched over her at all hours of the day, Winter gradually recovered. However, when her condition began to stabilize, new problems arose. When she was caught, one of the cables in the crab trap was wrapped so tightly around her tail that the blood supply to the tail was cut off. Necrosis developed, the skin began to peel and the tail began to rot. One day Winter's caregivers found two of her tail vertebrae at the bottom of the pool. Winter slowly regained her strength, but at the same time it became clear that she had lost her tail.

In a way Winter was lucky, even if she didn't realize it. She was born in the 21st century, and if an animal is destined to lose a limb, now is the time. A variety of innovative materials, from composite carbon fibers to flexible plastic materials with the ability to change shape, allow us to design artificial limbs for flying, flapping, running and swimming patients. Using such prostheses, scientists installed a new beak for an eagle, replacement armor for a turtle and an artificial leg for a kangaroo.

Sensors and identification tags attached to the bodies of animals can help save entire species, as they provide vital information for formulating conservation strategies, while artificial tails and feet represent the other end of the spectrum. They allow single injured animals to be put back on their feet (sometimes, quite literally). Artificial organs are not suitable for every animal. In fact, one of the challenges is the need to understand what will best serve a body that is not at all similar to the human body. But when we succeed in doing so, the prostheses designed and manufactured in an individual fit, allow us to help the injured animals one by one.

Dolphin cut off the tail

The Clearwater Marine Aquarium is located on an island off the Florida Gulf Coast. A few steps lead from the central entrance hall to an open deck overlooking a large pool of water, where two dolphins splash for pleasure. Winter is easy to recognize, instead of a long and thick tail she has a bent and short stump that thins out at the end of her body.

Even with her short tail, Winter seems to be comfortable in the water, and she glides across it and has fun just like her pool mates. To adapt to her new body shape, Sigla Winter practiced unique swimming techniques. Dolphins usually use their pectoral fins to balance themselves in the water, but Winter "cheats nature" and uses them as little oars. And since she lacks the pair of caudal fins characteristic of dolphins and used as their main organ of locomotion, Winter taught herself to swim like a fish, moving her body from side to side instead of up and down, as dolphins do. Unfortunately, however, this swimming position, typical of fish, creates unusual pressure on Winter's spine and causes it to curve unnaturally.

In the months after her rescue, her strange swimming method caused concern in the hearts of her caregivers and they feared that it would cause her irreversible damage. One of the Clearwater Marine Aquarium staff members raised this concern when he told Winter's story in a September 2006 interview with the US Public Radio Network. A prosthodontist named Kevin Carroll happened to be listening to the show in his car while driving to his office in Orlando. While listening to the story of Winter's shenanigans, he thought to himself: "I can put a tail on this dolphin."

Carroll grew up in Ireland, near a hospital in a small town, and when he saw the sick and injured children who came to the hospital for treatment, he became interested in repairing the human body. Carroll currently serves as vice president of the Hanger Company based in Austin, Texas, one of the leading bushing manufacturers in the world. Every now and then someone walks into his clinic with a three-legged measuring dog or a bird with its beak amputated. As an avid animal lover, Carol cannot help but dedicate the weekends to helping the injured animals. Over the years, Carroll, together with his colleagues at Hangar, developed prosthetics for a variety of animals: dogs, ducks, sea turtles "and any creature that happens to come our way," says Carroll. "I became a kind of Dr. Doolittle prosthetics expert."

When the aquarium management decided to allow Carol to gamble and try to build an artificial dolphin tail, he immediately began recruiting a work team. He had no doubt who he wanted as a partner: Dan Strzempka, an expert in prosthetics from the Hangar branch in Sarasota, Florida. Strzempka, who uses a prosthesis himself after a lawnmower severed his leg when he was four, is a native of Florida captivated by the magic of the ocean and the creatures that live in it.

Karol and Strzempka agreed to meet me at the aquarium and demonstrate to me how they dealt with the task. They look like an odd couple: Carol has a thin and frail body, he is completely bald and his face is decorated with a white beard. Strzempka, on the other hand, is tall, tanned and has a solid build. When we reach the dolphin pool, Strzempka bends over the railing and calls Winter: "Hey, sweetie! What's up, my love?" And Carol greets her with a good morning in a heavy Irish accent.

In the last five years, the two have spent countless hours next to the dolphin pool. Winter was unlike any living thing they had handled before. Their first task was therefore to understand how a body is built and functions. And so, they began to learn everything possible about dolphins. They read and collected every bit of information about dolphin anatomy and physiology and repeatedly watched slow-motion videos of marine mammals swimming to decipher the biomechanics of their body movements. Fitting prostheses to animals is indeed based on human medical treatment, but it often requires considerable ingenuity to succeed in the task. Building an artificial leg for an amputated person will not help fitting a prosthetic leg to an elephant or a dog. And so, just like MacGyver [the resourceful secret agent, hero of a television series that was popular in the 80s and 90s of the last century], prosthetic builders are therefore forced to find, design and build a creative solution adapted to each individual animal.

In Winter's case, the work plan was clear: Carol and Szczempka decided to create an artificial tail from plastic and dress it on what was left of her tail. But they soon realized that the real challenge would be finding a way to hold the prosthesis in place. It was clear to them that Winter would exert enormous force on the artificial tail while swimming, but unlike a person with a prosthetic leg, she would not put pressure on the prosthesis with all her body weight. "Water," Strzempka reminds me, "is a completely different environment than the one we live in." Apart from that, the skin of the dolphins is smooth, sensitive and delicate, and therefore also very vulnerable.

Amputees use soft pads to protect their stumps and prevent damage to the skin covering them. Carroll and Szczempka came to the conclusion that Winter would also need something similar. However, they realized that the normal pads used by humans would be useless for her. They will therefore have to create a completely new material, soft enough to protect her skin, sticky enough to stay close to a slippery surface like dolphin skin, and durable enough to not wear out with everyday use and exposure to a pool full of salt water.

They recruited a chemical engineer to help them, who conducted experiments on the components of the gel used in the pads to protect human stumps and tried to develop a version more suitable for use by dolphins. Some of the first prototypes he created looked promising, but when actually tested, their performance did not always meet expectations and in some cases even proved to be a complete failure. In one case, a warehouse where the material was stored caught fire and burned to the ground. ("It was a small warehouse," Strzempka reassures me.) But in the end, the engineer was up to the task.

"It's amazing stuff," says Carroll. At this point we are sitting in the trainer's office of the aquarium. Carol hands me a sheath made of the flexible gel: a white substance, vibrating and sticky to the touch. The pouch looks more like a giant piece of squid. In technical terms, the material is a thermoplastic elastomer: a mixture of plastic materials, liquid in origin, that can be shaped into a variety of shapes when heated. But the substance is commonly called "dolphin gel." To demonstrate the wonderful properties of the material, Karol takes a strip of gel that is about 60 cm long and asks Strzempka to hold the other end of it. He starts to step back, half a meter, a meter, three meters and the leash continues to stretch. When he leaves it, the gel band jumps back to the other side of the room. Strzempka holds the gel strip for show in his palm, the material looks like new, and there are no visible signs of deformation or stretching. The two smile with satisfaction. I have a feeling this was a well-orchestrated PR exercise. The gel also cushions effectively, and to demonstrate this, Carroll wraps his palm in the vagina and hits it hard with a heavy wooden hammer. He pulls his hand out of the vagina with a smile and shows it to me, whole and healthy.

swimming champion

Today, Winter is an experienced professional swimmer, and she happily wears a full-sized tail prosthesis that is anatomically adapted to her. To assemble Winter's tail, a dolphin trainer stands on a platform floating in the pool water. Upon hearing the agreed signal, Winter stabilizes herself in the required position, with her head facing down, towards the bottom of the pool, and the stump sticking up, above the surface of the water. First, the trainer wraps the stump in a pouch made of dolphin gel and then assembles the prosthesis itself, which Karol and Strazemka built precisely according to XNUMXD photographs and computer simulation of her body. The prosthesis has a sort of flexible, rubber-coated plastic mount that is worn over the protective sheath and embraces the stump left from the dolphin's tail. The pointed mount ends on the other side with a thin strip made of carbon fiber, which is screwed to an artificial bilobed fin. The entire device is held in place by air suction.

Although the prosthesis is shaped like a natural dolphin tail, it is made of various artificial materials, and Winter must be watched while the prosthesis is mounted on her body. Winter's caregivers must make sure, among other things, that the tail did not suddenly slip or get caught on some bone in the pool and detach from her body. That's why Winter doesn't wear it all the time. In fact, Winter only uses it during the day-to-day treatments she undergoes, when she performs, under the guidance of her trainer, a series of exercises designed to strengthen her muscles and give her a natural swimming position. The artificial tail does help keep Winter's spine in proper alignment, and she does wiggle her new tail up and down when it's assembled, instead of moving her body from side to side. "It's just wonderful to see her swimming like that, with the tail we made for her," says Carol. Since she started swimming with the prosthesis, the condition of the spasticity that Winter had after losing her tail has improved, and Carol hopes that the device and the swimming exercises will allow the dolphin to enjoy a long and healthy life.

However, despite the improvement in her condition, Winter will be forced to spend the rest of her life in the dolphin pool. A dolphin without a tail or with an artificial tail does not have many chances to survive in the wild. Moreover, it is still not clear how durable the prosthesis will be in regular use over many years. Winter will continue to depend on the close supervision of coaches to strengthen and maintain her swimming habits and doctors to monitor the condition of her spine. And in the meantime, Carol and Szczempka continue to make several new artificial tails every year because young Winter has not yet reached her final dimensions, and they change and adjust the design of the tail according to the changes in her body. They also aim to improve the prosthesis considerably. Strzempka, for example, is trying to find a way to incorporate a suction device into the prosthesis that will "suck" the air from it every time Winter moves her artificial tail up and down. Such a device will ensure a better seal and allow an automatically adjustable bushing to be built.

Winter's tail earned her celebrity status. Her story is depicted in books, video games and documentaries. In 2011, the movie "Dolphin Tale" was released, a XNUMXD movie from Warner Bros. based on Winter's life story. (The role of the prosthetics expert, or "mad scientist," as Carroll calls his character in the film, is played by Morgan Freeman.) The Clearwater Marine Aquarium's website and its gift shop are full of memorabilia commemorating Winter's character: T-shirts, postcards, magnets. And even tailless toy dolphins.

But Winter has become much more than a powerful marketing tool. She was the representative of the amputees wherever they are and a source of encouragement and inspiration for them. Children with prosthetic arms or legs visit the aquarium and many of them are even invited to meet Winter face to face in the dolphin pool. The meeting can work wonders in the minds of children, says Carroll.

Winter also helps amputees in more tangible ways. When word of the dolphin gel's miraculous properties began to spread, prosthetics specialists began ordering it for their human patients. The innovative material adheres to the skin much more successfully than the gel pads that have been used so far to protect stumps and is especially effective for amputee athletes whose prostheses tend to slip when they sweat. An avid golfer, Strzempka embraced the gel immediately after first trying it on his own prosthetic leg. "The stickiness of the gel is one of its big advantages, especially in Florida [where the humidity is high]," says Szterzemka. "After playing 36 holes of golf in one day, your skin will also become as smooth as the dolphin's skin." It wasn't long before the Hanger company began selling WintersGel pads to everyone - from experienced triathlon competitors to 11-year-old girls. "Animals give us so much," says Carroll. "We learn a lot from our work with them."


The article is adapted from Emily Anthis's book: "Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts", in coordination with Scientific American / Ferrer, Strauss and Giroux Publishing Ltd. (North America), Oneworld (UK / Australia). All rights reserved by Emily Anthis © 2013

on the notebook

Emily Anthes is a journalist from Brooklyn, New York. Her articles have appeared in Wired, Discover, Slate and other magazines. She has a master's degree in science writing from the Massachusetts Institute of Technology (MIT) and a bachelor's degree in the history of science and medicine from Yale University.

in brief

A female common dolphin named Winter lost her tail after being caught in a crab trap. Unwillingly, she taught herself to swim like a fish, moving her body from side to side, a swimming technique that caused her spine to curve.

Two prosthetists decided to build a new artificial tail for Winter: an unprecedented task. During the construction of the prosthesis, a new type of gel was created.

Today, Winter's artificial tail helps align her spine, and pads made of "dolphin gel" have been proven to be an effective means of protecting the stumps of amputee athletes as well.

And more on the subject

Winter's Tale: A Dolphin in Distress. John Barry in Tampa Bay Times, December 7, 2008.

Winter: The Dolphin That Could! A documentary produced and directed by David Yates and Steve Brown. On DVD. Clearwater Marine Aquarium, 2010.

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