Ramps assisted the animals during scenes of leaping, with trainers ready at both ends with treats and praise. The scene that shows a cat running on top of Buddy to escape involved a cat on one such ramp. Later, the scene was made to appear that the cat had leaped on the back of the dog.
The challenge faced by Guterman (who directed the computer-graphic movie Antz) was to decide when to use a live animal, a puppet or computer graphics, and how to maintain the same “character” in all of them. Breeds that generally showed more gentle temperaments were chosen, such as the exotic shorthairs who played Calico and the British shorthair who played the Russian blue. (The shorthair breed was also chosen because the cat’s rounder face and larger eyes made it look more kitten-like.)
The crew took no chances putting dogs and cats together, however. A Russian blue assassin puppet was used to rub against Lou – to show disarming friendliness in front of the unwitting humans. As soon as they were alone, the Russian blue spit up a spiked hairball and sent it spinning toward our young hero.
The hairball was, of course, a product of computer graphics, along with other deadly flying objects. The Ninja cats, played by another friendly breed called the Devon Rex, were a mixture of animatronics.
In its review, the AHA praised the makers of the movie for the lengths taken to care for all the animals, given without favoritism toward the on-screen antagonists. The animals themselves were exemplary in their cooperation, the report notes:
“One of the trainers commented that in the case of Noah, an Anatolian shepherd who played Butch, ‘If he’s not needed yet, he’ll just lie down somewhere on the set and go to sleep, even with 60 or 70 people working all around him.'”
One of the producers joked that he was so impressed with the animals’ discipline that he fired his assistant, and replaced him with a mastiff.