These animals lost limbs. Tech put them back on their feet

3D printed prosthetics can help dogs, sheep, alligators and other animals with limb loss swim or run again.

Erin Carson Former Senior Writer
Erin Carson covered internet culture, online dating and the weird ways tech and science are changing your life.
Expertise Erin has been a tech reporter for almost 10 years. Her reporting has taken her from the Johnson Space Center to San Diego Comic-Con's famous Hall H. Credentials
  • She has a master's degree in journalism from Syracuse University.
Erin Carson
6 min read

While Keating has a very dashing pirate peg leg, he also has a more modern 3D printed front leg. 

Nancy Miller

Mr. Stubbs was not like the other alligators. 

An Arizona Highway Patrolman found him in a tractor trailer along Interstate 10, one of several exotic animals being transported without a permit. The alligator, who would be dubbed Mr. Stubbs upon taking up residence at the Phoenix Herpetological Society, was missing a large portion of his tail.

While no one is completely sure how Mr. Stubbs lost his tail, the theory is that another, bigger alligator bit it off when he was a baby. A missing tail is a problem for an alligator. The appendage functions something like an extra limb, helping the animal propel itself through the water and keep its balance on dry land when it walks. The tail accounts for about 30% of an alligator's total body mass. 

So the Herpetological Society reached out to The CORE Institute, which specializes in orthopedic care, and its sister organization, a nonprofit called the More Foundation, with the wish for a new tail for Mr. Stubbs. 

"Certainly, this was the first time we'd had a request for an alligator," says Marc Jacofsky, executive director of research and education at the More Foundation. "The motto of our organization is 'keep life in motion,' and I didn't see anywhere where it says human life only." 

Alligator with prosthetic tail

Mr. Stubbs' tail is made out of a durable material, aptly named Dragon Skin. 

More Foundation

Jacofsky, the More Foundation and Midwestern University researchers approached the task traditionally -- at first. They took a mold of Mr. Stubb's backside, and then took a mold of a tail from the cadaver of a similarly sized alligator, and blended the two. Using a tough rubber silicone material called Dragon Skin, they made a flexible tail they could attach to Mr. Stubbs' residual tail. 


Everyone might have gone back to their swamp at that point, but Mr. Stubbs, like most living creatures, grew and changed over time -- meaning he needed a new tail just about every year. That involved dipping a 90-pound alligator's butt in rubber, annually, and scouting for yet another cadaver. That's when the foundation turned to 3D scanning and printing technology.

Using computer software, they scanned the alligator and scaled up his tail, digitally. It took about 150 hours to print, and about $1,000 worth of materials to create, but the result was a new, 35-pound Dragon Skin tail for Mr. Stubbs.

Best fit

While Mr. Stubbs is far from the first critter to end up with a human-made appendage, there's no hard data available about how many animals out there use prosthetics. One higher-profile prosthetics makers in the field, Derrick Campana, says on his site that he's "treated 20,000 furry patients with mobility devices" since 2004 alone. 

At North Carolina State University's College of Veterinary Medicine, doctors Simon Roe and Natasha Olby tell me over Zoom calls about their work on everything from prosthetic joints (more Roe's speciality) to the use of carts for paraplegic or neurologically challenged animals (Olby's area). 

Animals with mobility issues have a spectrum of available options, Roe says. There are the prosthetics that slip over residual limbs. Less commonly, some doctors implant prosthetics directly into bones and through the skin. Or, as was the case for Olby's late dachshund Mickey, a cart for his back legs helped him zip around and even bully his other dog siblings by blocking doorways. 

Overall, though, Roe says prosthetics for animals aren't as prevalent as you might think, despite all the feel-good videos of animals with new limbs you might catch on social media. 

You're not exactly going to run into a video where the owner says, "I spent $3,000 and 40 hours trying to get my dog to wear a prosthetic, and all he would do is stand there, shake it off and run away," Roe says.

Prosthetics and even carts aren't an easy or all-encompassing fix. While dogs, for example, tend to adapt to carts pretty well, they can't be in them all the time, Olby says. 

"If they're going to be active, [owners] can pop the dog in the car and off they go. And the dog can perform extremely well," she says. Still, if they want to lie down or rest, they can't do that while in a cart. 

Pegs and printers

Not all pet owners are willing or financially able to take on the challenge of finding a vet and a prosthetist to work with their furry pal over the long term. 

Luckily for Keating, an almost 6-year-old greyhound-boxer mix, his humans are up for the job. In fact, it is their job. 


Keating shows off his 3D printed leg.

Nancy Miller

Mark and Nancy Miller own Miller Prosthetics and Orthotics in Belpre, Ohio. In 2014, they received an email from a listserv they were on asking if anyone would be willing to adopt a puppy who was born without part of his right front paw.

The Millers drove down to the shelter in Chattanooga, Tennessee, and brought Keating home. 

Over the years, Keating -- who Nancy describes as happy and "obviously well-fed" -- has had a few prosthetics, including a hand-turned peg leg that helped win him a costume contest held at a fundraiser for a local animal shelter (he was a pirate). 

As solid as that pirate leg was, though, the Millers had been interested in getting into 3D printing. They decided maybe Keating's leg could be their first project. 

There were challenges along the way. While it seemed like using a 3D scanner might be an easier way to get a scan of Keating's leg, it turned out the scanner couldn't really interpret dog hair. Other scanners took longer, meaning the Millers would have to get a sedative from the vet so that Keating would hold still during the scan. 

Mickey the dachshund

Mickey used a cart to get around. 

Natasha Olby

With the help of a prosthetics instructor in Tulsa, Oklahoma, named Rick Sevier and the maker space at West Virginia University of Parkersburg, in July 2019 Nancy was able to print a blue and black leg that says "Keating" on it, based on her husband's design.

"As long as it fits, he'll use it and he'll run with it," Nancy says. "He doesn't think about it. He just wants to go," She and Keating even did a three-mile turkey trot race in November on his 3D printed leg.

Keating, now a certified therapy dog, has become something of a greeter and ambassador at the Millers' clinic. He might be their laziest employee, Nancy says, but he's a comfort for folks in the office. And, in classic dog fashion, he's able to get the newspaper every morning. 

Felix, free

When there aren't any visitors at the Woodstock Farm Sanctuary in High Falls, New York, the sheep get to roam freely about the 150 acre farm -- all except Felix. 

Felix came to the sanctuary in 2008 as a baby after a predator of some kind had bitten off part of his back left leg. While he could still move around on his other three legs, he couldn't cover as much ground as the other sheep.

"It was always sad to see Felix not being able to follow his friends, [and] always be left behind," shelter director Hervé Breuil tells me over the phone. 

When Felix was about four years old, and showing signs of stress on his other limbs, the sanctuary decided to get him a prosthetic leg. Ultimately, after trying more traditional prosthetics, Felix ended up with a 3D printed leg, created with help from SUNY New Paltz researchers.

Sheep in a pasture

Felix and friends.

Woodstock Farm Sanctuary

Felix is just one of several animals the sanctuary has helped, including a Jersey cow named Fawn, who uses orthotic boots to get around, and a goat named Albie who's getting a brace to help accommodate the arthritis he's developed in his old age. 

The sanctuary has worked with prosthetists and universities to figure out how to bring increased mobility back to farm animals. 

"When something is wrong with [farm animals] they're put down by the farmers -- they just don't have time and or the money to put in them," Breuil says. Fawn for example, required surgery at Cornell University. All in, she's cost the sanctuary about $35,000. 

Breuil says it's all about seeing these animals as individuals, deserving of a good quality of life. Felix, at least, seemed to agree.

"That was a beautiful thing to witness," Breuil says. "He [could] just be himself and with his friends."

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