'I can't tell the difference': how a CGI canine emerges as top dog in new Harrison Ford film

We discover how the actor appears on screen alongside a furry animal, despite not filming with one

Harrison Ford stars as John Thornton in the latest adaptation of 1903 novel ‘The Call of the Wild’. Twentieth Century Fox

With a career spanning more than six decades and starring roles in two of modern cinema's most enduring franchises to his name – as Han Solo and Indiana Jones – as well as lead roles in cult classics such as Blade Runner and American Graffiti, Harrison Ford is ­undoubtedly one of the true Hollywood greats. Noted film critic and historian Roger Ebert described him, in a 1993 review of The Fugitive, as "the great modern movie everyman". 

It's perhaps surprising, then, that at 77, the renowned actor has seemingly chosen to fly in the face of that long-standing maxim of the profession that you should never work with children or, in the case of The Call of the Wild, animals.

The film, which is based on Jack London's much-loved 1903 novel of the same name, tells the interlinked stories of Ford's John Thornton, a distraught father who heads for the wilds of the Gold Rush-era Yukon to find himself after his son's death, and Buck, a loveable St Bernard-Scotch shepherd dog, who also finds himself in the snowy northern wilds after being kidnapped from his Californian home.

Ford is quick to set the record straight about undertaking the dreaded animal-related work – and reveals he actually didn't do any at all. "One of the most interesting details of shooting this film was that there were no dogs to work with," he says. "There was a human stand-in for Buck, to organise my eye line and to give me someone to participate with emotionally. It was, at first, a bit challenging, but then became quite good fun."

The film's doggie cast, which includes several computer-­generated huskies in supporting roles, was originally planned as a purely CGI endeavour, but as production progressed, the film's FX crew began to incorporate more photography into their digital creations. Then, several weeks into shooting and with practical issues around making Buck sufficiently convincing, director Chris Sanders's wife, Jessica, stumbled across a real St Bernard-Scotch shepherd rescue dog for adoption online, who was, incredibly, also called Buck.

This coincidence was too much for the director to ignore and the newly adopted dog was scanned and used as the basis for the Buck we see on screen. Although Buck Junior was invaluable in the CGI process, it was his human stand-in – former Cirque du Soleil performer and motion capture specialist Terry Notary – who was the crucial piece in the puzzle of bringing the dog to life on screen.

In the early stages of production a tennis ball was used as a marker for the actors during Buck's scenes, with the CGI dog to be added later. But Notary proved up to the task of playing a dog, having studied the movement and mannerisms of the animals for hours to prepare.

The film's producer, Erwin Stoff, admits he was not ­initially convinced that having Notary crawling round the set was a good plan. "It was an odd idea and I didn't know how the cast would react to it," Stoff says. "You've got a grown man who is on all fours, in a funny grey suit with these prosthetic front legs playing a dog. But it turned out to be a genius move because Terry gives such a committed portrayal that it improved every actor's performance. Terry brought the emotionality of Buck to the set."

Ford is equally effusive about the performance of his co-star. "I spent more time with Terry than I did with anyone else on this film," he says. "We helped each other accomplish what the other needed. I was acting for him as he was acting for me. We were there for each other."

The Call of the Wild had its first big screen outing in a 1923 silent film, while actors such as Clark Gable, Bryan Cranston and Rutger Hauer are among the big names to have starred in movie adaptations of the novel since then. Even the 1978 TV special What a Nightmare, Charlie Brown! was an adaptation of London's novel.

It's fair to say that photo-realistic, CGI reimaginings of much-loved classics haven't been universally celebrated recently – last year's remake of The Lion King, for one, had audiences and critics divided with its creepily, yet not quite, realistic computer-generated cast of animals.

However, Ford says he is certain his latest film will pass the audience test. "I've been shown moments of animation in this movie which I mistake for a real dog – they can do that completely. I just can't tell the difference," he says. 

"I love storytelling – it doesn't matter to me whether I've got a blue screen or reality. One of the things we did, which I think is important, is that we built physical sets throughout the film, and we may augment them above the first or second story, and put them in a location that we didn't actually film in with CGI magic. It allowed us that convenience to shoot someplace other than the frozen tundra."

For all the convenience of CGI, for Ford it's that storytelling, and the relationships between the lead characters, that will be key to the film's success. "Thornton and Buck become companions in this journey, emotionally bonded, and they face danger and adventure together," he says. "I was touched by that journey and the relationship between these two characters. The one thing technology [alone] can't do is tell a story."

Ford may have bowed out of the Star Wars universe with 2015's The Force Awakens, but he will reprise his role as swashbuckling archaeologist Indiana Jones when the fifth film in the franchise begins shooting this summer. The American actor's place as a true great of family entertainment seems assured and he clearly hopes that The Call of the Wild will be added to his finest family-friendly moments on screen.

"The luck of my career is that I have done a lot of films that are family films and their success has allowed me to do other things that I'm interested in, and explore other subjects and other kinds of characters," he says. "But as generations come along, they're reintroduced to me through the Star Wars or Indiana Jones series and hopefully this will fall into that area, of the gift that keeps on giving."

The Call of the Wild is in cinemas across the UAE from Thursday, February 20