For almost as long as there have been images of celluloid humans to project onto flat white screens in darkened rooms, there have been celluloid monsters to accompany them.
We've had demons, vampires, werewolves, aliens, shapeshifters, cyborgs, zombies, even an oversized monkey called Kong. But none has proved more enduring or malleable or fascinating to filmmakers and audiences alike than the one monster that did actually exist: the dinosaur.
The first of these - a Brontosaurus called Gertie - celebrates her 100th anniversary in February. She was able to walk among us in 1914 thanks to animation techniques which, by today's standards, are themselves primeval: thousands of sheets of rice paper laboriously inked over thousands of hours by illustrator and showman Winsor McCay, who initially used Gertie as part of his vaudeville act.
Fast forward a century, and this week it's a Pachyrhinosaurus called Patchi who'll be thrilling audiences as the star of 3D family spectacular, Walking With Dinosaurs. Co-directed by former New Scientist journalist and BBC natural history filmmaker Neil Nightingale, Walking With Dinosaurs mixes live action settings with technical whizz-bangery to tell the life story of a single dinosaur living in modern-day Alaska in the late Cretaceous period, around 70 million years ago. It was filmed in Alaska and New Zealand and, while some CGI was employed, it was mostly made using the so-called LIDAR (light detection and ranging) technology developed by James Cameron's special effects company, Cameron Pace Group.
"Dinosaurs are the most amazing creatures to have ever existed on our planet," says Nightingale. "In four and a half billion years of Earth's existence, there have been no creatures more dramatic or terrifying. Dinosaurs fascinate us because they represent a sort of safe danger. You can be scared of them but not too scared because they're long gone. They're not going to come out from under the bed or pounce on you in the dark."
But a monster is so-called for a reason. Gertie and Patchi, the creatures that bookend this century of movie dinosaurs, certainly wouldn't jump out from under your bed but there are plenty of other screen dinosaurs which would happily pounce on us in light, dark or gloaming. Think of Godzilla (or Gojira to give him his original Japanese title), described in the classic 1954 film as a "Jurassic monster" of the Tyrannosaurus Rex variety who also happens to be radioactive and keen to lay Tokyo waste. In Roland Emmerich's 1998 version it's New York that's under attack, but otherwise the basic premise is the same. The big movie monster comes, the little movie people run away. Some escape, lots don't.
There are many other examples, from the tail-end of the silent era - the 1925 adaptation of Arthur Conan-Doyle's 1912 novel The Lost World, for instance - through to 21st-century horror flicks like 2004's Roger Corman-produced Dinocroc. And let's not forget the B-movie "creature features" of the 1950s and 1960s on which Corman made his name - films like Dinosaurus!, which employed stop-motion animation for its scenes involving a Brontosaurus and a Tyrannosaurus Rex, and which would have employed Steve McQueen too had actor Ward Ramsey not been preferred.
Proof that dinosaurs were still appealing to audiences in the mid-1960s can be seen in the decision by British film company Hammer to have the cavemen and women of One Million Years BC encounter a range of creatures from the Jurassic and Cretaceous periods. This despite the fact that dinosaurs died out 65 million years before humans emerged to light fires and decorate caves. In a famous scene from the film of 1966, a fur-bikini-clad Raquel Welch watches as a Ceratosaurus and a Triceratops battle it out. Next to that deliberate historical clanger, it's barely worth noting that those creatures didn't co-exist any more than humans and dinosaurs did.
Animating the creatures in One Million Years BC was celebrated special effects creator Ray Harryhausen, who had also worked on the original 1933 version of King Kong (Kong fights a Tyrannosaurus Rex, you may remember, and the film also features a Stegosaurus and a Brontosaurus). In a later interview, he said the film wasn't intended for "professors". How right he was.
Dinosaurs featured only rarely at the box office in the 1980s, but in the 1990s they were to get star billing once again. This latest chapter of the story begins in October 1989 when a filmmaker, Steven Spielberg, and a doctor-turned-author, Michael Crichton, meet in the director's Los Angeles office to discuss a screenplay Crichton has written about his days working in a hospital emergency room. It will become the TV series ER, but that's still five years away.
"I happened to ask him what else he was working on, aside from this screenplay," Spielberg would later tell his biographer, Joseph McBride. "He said he had just finished a book about dinosaurs … I said 'You know I've had a fascination with dinosaurs all my life and I'd really love to read it.' So he slipped me the galleys."
Spielberg wasn't lying. He grew up in Haddonfield, New Jersey which, as any paleontologist will tell you, is where fossil hunter William Parker Foulke discovered the world's first near-complete dinosaur skeleton in the summer of 1858. Foulke called it the Hadrosaurus in honour of the town. As a schoolboy, Spielberg would visit the area in which the remains were found. His love of dinosaurs started there.
Where it ended up, of course, was on screen, in his 1993 blockbuster Jurassic Park, based on Crichton's novel of the same name. As well as breathing new life into the dinosaur genre, he gave us one of the decade's most memorable screen villains - the Velociraptor - and spawned a franchise that currently consists of three films. By the time it clocked up its 20th anniversary this year, Jurassic Park had earned over $1 billion and the franchise itself close to $2 billion.
But the appeal to filmmakers of pitting dinosaurs against humans isn't just down to their size, their speed and their ability to flick a Jeep over a tree with a single swish of a tail. It's deeper than that. It allows them to explore the sort of themes that Ray Harryhausen's professors might actually approve of. In Jurassic Park it's genetic engineering, biological tinkering and chaos theory. In those many films in which white Europeans stumble upon previously isolated jungle ecosystems, it's ecology, colonialism and globalisation. Elsewhere it's scientific hubris, greed, fear of technology, even the threat of communism and the horrors of nuclear war.
In Godzilla it was that last subject which pre-occupied director Ishiro Honda, who had worked under the great Japanese filmmaker Akira Kurosawa and who had spent the war years as a POW in China.
Certainly, few who saw the film on its original release in 1954 would have been under any illusions about the point he was making in having a radioactive monster attack a Japanese city. In case anyone did, an early scene on a commuter train where the rampaging dinosaur is being discussed has a woman tell a fellow passenger that she survived the bombing of Nagasaki and has no intention of not surviving this threat. She doesn't, of course.
Honda's plot was a straight lift from an American film of 1953, The Beast From 20,000 Fathoms, in which an atomic test in the Arctic unfreezes a 100ft-long dinosaur. Having been in a deep sleep for 100 million years it wakes up hungry and sets off to eat Manhattan. Here the metaphor is communism: the dinosaur is called a Rhedosaurus. Get it?
Emmerich's 1998 version borrowed much of its action sequences from Jurassic Park, gave Godzilla a Predator-like ability to blend in with its surroundings - and blamed the French for the ill-judged nuclear test that begat the beast in the first place. The film was panned on release but, post 9/11, its New York setting, its Francophobia and the fact that half an hour in there's a reference to the 1993 World Trade Centre bombing have brought it a certain cachet, at least among internet conspiracy theorists.
And now we have Walking With Dinoaurs in 3D. The film takes its title and much of its form from the acclaimed BBC nature series which began airing in 1999 with narration by Kenneth Branagh. And for much of the first decade of the 21st century, that's how prehistoric creatures have been presented to us: as a subject for serious scientific study and education. Again, Ray Harryhausen's professors would approve.
But as the movie dinosaur clocks up its centenary and prepares for its second century, there are signs that things are changing in that regard. In 2014, British director Gareth Edwards will bring yet another version of Godzilla to our cinema screens. This time it's "scientific arrogance" that's to blame for the monster's re-emergence, according to studio Warner Bros. Then, in 2015, the biggie: a fourth in the Jurassic Park franchise will be unleashed, titled Jurassic World.
Plot details are sketchy, so watch this large, footprint-sized space for more on that. What is clear, however is this: there's still plenty of life in those old, old bones.
Walking With Dinosaurs is released on Friday. A 20th anniversary edition of Jurassic Park is out tomorrow on Blu-Ray 3D