If Noah were still around and looking for on-ark medical care for his passengers, he would do well to check out the Sisters Veterinary Clinic in the town of Sisters, Oreg. There, the vets, like Noah's animals, come in two by two—in this case, identical twin sisters Susan Conner and Sharon Sharpnack.

In 1967, Susan and Sharon became the first female identical twins to graduate from a U.S. veterinary school (the University of California, Davis). Both then married graduates of the same school. After Susan's marriage ended in 1977, she moved to Oregon. Sharon and her husband moved there four months later and opened the clinic. At first, Susan worked in a nearby town, but eventually joined her sister and brother-in-law's clinic. In 1984, Sharon's marriage ended, and the sisters took over the practice together. "We're the same age; we have the same thinking and the same training," says Sharon.

The 48-year-old twins, who have two children each, grew up in Santa Barbara, Calif., where their parents were beauticians. They got their first pet, a dog, when they were 5. That was followed by a rabbit, guinea pigs, rats, parakeets, canaries, cats, skunks, opossums, chinchillas and a monkey. "We lived in town, but we still raised baby goats right in our yard until someone turned us in," says Susan. "One time, we had a pet rattlesnake. Mother got really mad."

The menagerie grew as other children realized that the girls could heal animals. By the time they were 10, they had made their career choice. "One day the local vet asked us if we'd like to watch him spay a cat," says Sharon. "That was it. We thought that was so neat."

Now, though domestic animals make up the bulk of their practice, the sisters' proximity to the local forests means that more exotic cases sometimes show up—from a golden eagle wounded by poachers to dogs with faces full of porcupine quills.

The twins, who as teenagers sometimes switched clothes in the bathroom when they were on double dates, play it straight these days. Still, admits Susan, "When I have a case that doesn't work out real well, it's tempting to say, 'No, I'm not the one who worked on your pet.' "