Air Ambulance said their enhanced doctor and paramedic team were called to the incident
Adam's life was saved by Magpas Air Ambulance crew who were in the area at the time of the accident.
Magpas' critical care paramedic Dan Read said: "Adam's lungs were bleeding and there were lacerations to his liver and kidney, his right iliac artery was lacerated, he had a shattered pelvis and almost all of his ribs were fractured.
Magpas Air Ambulance is a charity based in Cambridgeshire, which responds to traumatic emergencies in the east of England.
Antonia Brickell, from Magpas
air ambulance, denied reports that visitors had been "running in terror", adding: "The visitors were safely evicted from the zoo.
A Magpas air ambulance spokeswoman said the man had been given enhanced pain reliefat the scene.
The Magpas team assessed the patient, who suffered serious injuries, and put measures into place to keep him warm as his body temperature had dropped considerably.
Dr Nick Foster, from the Magpas
charity, said: "The man who survived was very lucky.
Magpas Air Ambulance's Dr Saad Jawaid gave Malcolm powerful pain relief and sedated him to ease his agony.
The garden fence had to be broken for Magpas paramedics to get him out and fly him to Addenbrooke's Hospital in Cambridge.
Emergency medical charity Magpas
was called to the incident at 1.30pm on Monday and paramedic Andy Bates and Dr James French rushed to the scene.
MOON EMPEROR returns to the fray in the 3m2f Magpas
Lifesavers Handicap Hurdle (5.55) at Huntingdon today having not been seen since finishing down the field on Southwell's Fibresand in December 2007.