John Y. "Doc" Henderson , circus veterinarian in United States Born 1907-11-11 in United States dead 1991-06-14 in United States . For over 40 years he was veterinarian of Ringling Bros. and Barnum & Bailey Circus looking after the world’s largest traveling menagerie. He is recognized as an outstanding authority on the care and feeding of circus animals. Henderson went into WWII in 1944 and served until 1946, rejoing the circus with his new wife, Martha, an aerialist.