Fans of the PBS series “Nature” are used to having their breath taken away by the photography, but they’re less accustomed to having their heartstrings tugged. Wednesday’s installment, “My Bionic Pet,” about animals with disabilities, goes for the emotions. It’s one of three programs this week that prove that television about nonhuman creatures can be more than mere pretty pictures or idiotic turtle wrangling.

“My Bionic Pet” introduces a startling array of animals that, through the intervention of caring and innovative people, have been given a chance to overcome hardships. A pig with deformed rear legs has been fitted with a sort of hind-end wheelchair. A horse, a llama and several dogs have prosthetic legs. A swan that has had its beak mangled, presumably by a snapping turtle, is shown being fitted with a molded alternative.

The field is young enough that the specialists involved are often making things up as they go along.

“We have to modify things, because there’s really nothing out there,” says Dr. Greg Burkett, a North Carolina veterinarian, describing how he put the swan under to do the beak modification. “The anesthesia mask started out as a Sprite bottle.”