i am a veterinarian. I study prevention, diagnosis, and prevention of non human animals.
Sounds interesting! Do vets study and diagnose all animals or just some?
It depends. The scope of veterinary medicine is very wide, and covers both domesticated and wild.
Do you happen to know when vetenarians became common?
Veterinary medicine
Veterinary medicine is the branch of medicine that deals with the prevention, diagnosis and treatment of disease, disorder and injury in animals. The scope of veterinary medicine is wide, covering all animal species, both domesticated and wild, with a wide range of conditions which can affect different species.
Veterinary medicine is widely practiced, both with and without professional supervision. Professional care is most often led by a veterinary physician (also known as a vet, veterinary surgeon or veterinarian), but also by paraveterinary workers
In 1972 Dinnes founded Dinnes Memorial Veterinary Hospital of Santa Clarita, California and was the first veterinarian to completely devote veterinary practice to non-domesticated animals, limiting his practice to zoo and aquatic animal medicine and surgery. 
Dinnes was a consulting veterinarian for the 1983 adventure film "The Golden Seal".
In 1984 he was chosen as one of eight veterinarians by the American Veterinary Medical Association to form the American College of Zoological Medicine.
Dinnes founded the International Zoo Veterinary Group, providing consulting in disease prevention, quarantine