The sequence with the tiger in the subway tunnel was shot from 1:00 a.m. to 3:00 a.m. in the morning. The tiger got loose in the subway station and hid in a bathroom before deciding to go on top of a train. Subway station employees were prevented from entering the station until the tiger was finally caught.
An elephant stepped on director Francesco Prosperi's foot during the filming of the sequence with the elephants on the airport runway.
Three animal handlers were present on the set with tranquilizer guns for all the scenes involving various animals.
Antonio Di Leo was almost decapitated by the polar bear in the scene where the bear swings one of its paws at him, narrowly missing his head.
Antonio Di Leo took a tiger cub home with him and kept it for fifteen days. Aldrich was specifically cast in the lead role because he had previously worked for a circus as an animal tamer, and was comfortable working with animals.
Giancarlo Triberti: Animal handler, as the man who gets attacked and killed by the tiger in the subway car.