(CNN) -- As they whinny in pleasure, rear up in distress or paw the ground impatiently with their hooves, it's impossible not to feel that the animals on stage before you are living, breathing beings.
Yet the life-size puppets in acclaimed play "War Horse" are fashioned from nothing more than cane, cloth and aluminum to a simple, even crude design.
Produced by the UK's National Theatre, the hit show is now being adapted for the big screen by Steven Spielberg. The play follows a farm boy called Albert and his favorite steed Joey, who are parted at the outbreak of the First World War when Joey is recruited to the battlefields of France.
Its ability to reduce adults and children alike to tears has made it a hit in London's West End and last month a second production opened at the Lincoln Center on Broadway. It has already been announced that it will receive a special Tony award for its puppetry.
South African company Handspring, which has been pioneering large-scale puppetry for adults since 1985, designed and made the horses in an intentionally pared-down style.
"There's a drawn, sketched quality to them," says Handspring's Basil Jones. "In terms of the proportions of the horse it's naturalistic, but the detail is rather abstract -- so that the realism comes entirely from the movement."
Performers in New York tasked with manipulating the 8-foot (2.4 meter) puppets -- each of which takes three people to operate -- have had to follow in the footsteps of their London counterparts in learning equine graces.
"We went on trips to visit the mounted police to get a sense of how real horses move," says Adrian Kohler, who founded Handspring with Jones. "It's crucial to get the legs going in the right sequence, so that the sound of the hooves on the stage conjures up a horse even with your eyes closed.
"That takes quite a while -- there's a lot of going round and round the room counting, 'One, two, three, four.' You learn to walk, then trot, then gallop. Cantering is the only thing we can't do -- because it involves having three feet off the ground at once."
Next is learning the physical vocabulary of the animal, in order to express emotions and thoughts without the use of speech.
"The ears and the tail are the most visible emotional indicators to the audience at a distance," says Kohler. "If the ears are pinned back against the head it means fear or anger, and if they're moving around more then the horse is at ease.
"When the tail is raised upwards the horse is excited, and when they're scared they put their tail between their legs like a dog."
The show's directors have given the puppeteers free reign to be unpredictable on stage -- letting the spirit of the animal dictate their precise performance each night and keeping other actors who are playing human characters decidedly on their toes.
The spontaneity of the horses' actions is all the more incredible considering that the puppeteers working each animal -- two inside the body and one operating the head -- can't so much as whisper to each other because they are wearing microphones.
"They talk to one another using intakes of breath," explains Kohler. "A sudden sucking in of air means, 'I'm going to go somewhere now,' and the other two just follow. You might imagine the head makes all the decisions, but in fact they all make different decisions at different times."
Just as the design of the puppets is pared back, the key to making their movement feel real is keeping it simple. "We are minimalists -- the secret of our puppet manipulation is that we do very little," says Jones.
"Central to our philosophy as puppeteers is breath -- you have to believe that even though someone is sitting right at the back of the auditorium, they can see the puppet breathing. That's about an ability to trust the presence of your puppet on stage and know that you don't need to do too much to make it come alive. Stillness is as indicative of life as movement."
There's only so much control you can have over a puppet, however -- as the puppeteers have discovered when horses' feet and legs come loose during performances. A team of people waits backstage each night to make hasty adjustments and replace broken parts during scene changes.
With the UK production now having run for four years, most of the body parts of the main horses are no longer original.
In New York, the designs have been tweaked somewhat to make them lighter -- to the gratitude of those under the saddle, who also have to carry the weight of human riders.
And with productions due to open in Toronto and on tour in the U.S. next year, Handspring's workshop in Cape Town is doing overtime making new sets of horses.
It seems that mere cane and cloth have the ability to bewitch people all around the world.
"I think the audience empathizes for a creature that is struggling to be like them, for a dead object struggling to live," explains Kohler. "And that very struggle is what allows them to be empathetic towards a puppet in a different way than towards an actor."