Suppose someone working for a national park or wildlife reserve needs to capture a wild roan antelope to treat its infected shoulder?  To chase it down and rope it, then haul it, struggling and terrified, in a truck, may cause “capture myopathy”, muscle overstraining damage and resultant death resulting from the stress of capture.  Death from heart failure might also result.  Efforts to help the antelope might actually kill it.  Fortunately, years ago veterinarian Antonie Harthoorn made it possible to safely tranquilize such an animal with no capture myopathy.  Dutch born Antonie Marinus Harthoorn, known to his friends as “Toni”, developed the first large-animal tranquilliisers that revolutionized effective capture and transport for veterinary treatment as well as relocation.   

An unidentified game guard, Ian Player, George Korelin, Harry Makela and an uncredited assistant prepare a blindfolded white rhino for transport, in a scene from Rhino!, inspired by the real life conservation work of the Natal Parks Board. CREDITS: MGM/Ivan Tors Films

   Born in Rotterdam on August 26, 1923, Harthoorn spent most of his youth in England, since his father, who worked for the Unie Company, moved to England when Dutch Margarine Unie merged with the British Lever Brothers to form Unilever.  Harthoorn studied veterinary science at the Veterinary College in London. He enlisted in the Army during World War II and was one of the first to parachute into the Dutch town of Arnhem during the relief of the Netherlands by Allied troops. After the war Toni graduated and at the universities of Utrecht and Hannover earned his doctorate.  

    Dr. Harthoorn taught at the veterinary college in Nairobi, Kenya.  There he studied the effects of sedatives on mammals and in collaboration with a team invented the M-99 (etorphine hydrochloride) capture drug and refined the tranquilliser gun which fires darts containing the drug. Tranquilliser darts can also be fired by blowgun.  Dr. Harthoorn’s “flying syringe” is a refinement of the tranquilliser gun invented years before by New Zealand pharmacist, inventor and veterinarian Colin Murdoch. This technology is today used in moving large hoofed stock to areas where they need to be relocated due to urban development or poaching.  Since capture myopathy results from prolonged confinement and exposure to human handling, darting animals for treatment and transport minimizes the stress of handling and has made possible survival of hundreds of animals, particularly hoofed mammals that might not have endured these ordeals. Different spectra of drugs and different doses are needed for animals of similar sizes; a Cape buffalo, for example, needs different drug combinations and doses than does a young rhinoceros of equal weight.

Film and television producer and zoologist Ivan Tors relaxes in the back of a station wagon with one of the lionesses raised at “Africa, USA”, a ranch and filming facility in California that doubled for East Africa in scenes for many Ivan Tors television series. CREDITS: MGM/Ivan Tors Films

  Toni Harthoorn married fellow veterinarian Susanne Widrich and they had several children.  Game warden George Adamson of Born Free fame mentored Susanne and helped the couple establish a wild animal orphanage.  The two veterinarians helped save thousands of animals stranded on small islands resulting from the flooding of a large area caused by the Kariba Dam in 1959-1960 in present day Zimbabwe (then Rhodesia).   Kenyan farmers nicknamed Toni “Daktari”.

The cast of Daktari. Left to right: First row, seated, Marshall Thompson as Dr. Marsh Tracy, Toto the Baby Chimp as herself, and Yale Summers as veterinarian in training Jack Dane. Second row, standing: Cheryl Miller as veterinary assistant in training Paula Tracy, Hari Rhodes as veterinarian in training Mike Makula, and Hedley Mattingly as District Officer Hedley. CREDITS: MGM/Ivan Tors Films

    Ivan Tors was a zoologist turned screenwriter and film and television producer with many successful series like Sea Hunt and Flipper to his credit.  He visited the Harthoorns at their animal orphanage in the early 1960s and accompanied the Harthoorns and Ian Player, older brother of famous golf professional Gary Player, as they used the tranquilliser darts to capture rhinos and other animals for lifesaving medical treatment following injuries in poachers’ snares.  Ivan Tors produced two Harthoorn-inspired Metro Goldwyn Mayer (MGM) motion pictures: Rhino!  and Africa: Texas Style.  He became co-owner of “Africa, USA”, a ranch where he also produced Clarence, the Cross-Eyed Lion. Dr. Marsh Tracy was introduced in the latter film. Daktari was the television series that followed that year.

Paula Tracy (Cheryl Miller) , Clarence the cross-eyed lion, and Dr. Marsh Tracy (Marshall Thompson) appear in a scene from Daktari, inspired by the real life work of Antonie Harthoorn. CREDITS: MGM/Ivan Tors Films

  Like the real life Dr. Harthoorn, the main character of Daktari wrote books on veterinary work with wild animals. With the help of a family member and a team of professionals, he ran an animal orphanage.  Susanne was a technical advisor for Africa: Texas Style and Toni was technical advisor for all four productions.  At times the productions had lapses in authenticity but no one could deny that they were educational and spread interest in conservation.

    Ivan Tors’ interest in their work coincided with a tumultuous time in Toni Harthoorn’s life and career.  Work in East Africa ended in 1963 when, after Kenya’s independence, Antonie Harthoorn’s position was unceremoniously ended and the college replaced him with one of his PhD students.   He moved to South Africa and continued his work.  The Harthoorns divorced in 1970.  Toni and his able assistant Ian Player continued working to save many wild populations of the white rhinoceros in cooperation with the Natal Parks Board.  

   In 1972 Toni Harthoorn married Linda Margaret Pearsall of South Africa. Linda, who was qualified in Nature Conservation and Wildlife Management, assisted in the capture and release of hundreds of animals.  The couple wrote books and presented scientific papers at international conferences when time permitted. Because of the collaboration of the Harthoorns, Ian Player and the Natal Parks Board, the Hluhluwe Imfolozi Park reserve in northern KwaZulu Natal was established.   Linda and Toni stayed together until 1977.   Dr. Harthoorn continued his practice of veterinary medicine; he was also a homeopath and naturopathic physician.  He made his home in the Pretoria area and lived with his children until he passed away on April 23, 2012.  We all owe him our thanks for his efforts to maintain biodiversity.