This inspiring YouTube Video, which went viral recently, showed millions of viewers that a dog is still a dog, even with just two legs. However some veterinarians think the strain put on the dog can cause joint and mobility issues later in life. So doctors have been increasingly turning to prosthetics, including wheelchairs and other mobility devices designed to improve their quality of handicapped dogs' lives. Orthopets, a company which helps 2,000 animals per year overcome their limitations, says most devices cost between $150 and $2000, but can cost more in some cases. The owners of the dogs in this video, Amanda Giese and Gary Walters, co-founded Panda Paws Rescue, an organization dedicated to supporting the needs of special care and hospice dogs. In the last 19 months alone, they have placed 3500 dogs including 10 which are two-legged. Of those 10, nine are using wheelchairs. Duncan, the star of the video, had his two deformed back legs amputated, and he was not a candidate for artificial limbs or wheels.