fours. gary tuchman has more on today's edge of discovery. >> reporter: it's been called the walter reed for dogs. a high-tech hospital in san antonio, where the four-legged troops that serve our country get treated. >> medicine has changed over the years. we want to do what is best for the dog, and also if possible return the dog to work. >> reporter: the $15 million facility is top veterinary specialists on staff. and state-of-the-art tools and rehab equipment. >> my role at the hospital is to provide rehab therapy to all of our military working dogs. >> here we go. good boy. each is individualized. it's not a cookie-cutter. >> reporter: some dogs are treated onsite in war zones. but those that need more therapy come here. and dogs can also show signs of ptsd, just like people. >> they're great dogs and they work hard. but they have a really hard time conveying what is going on inside their heads. so we really have to rely on what they show was their behavior. >> reporter: most dogs are rehabilitated and return to