My brother Jerry and I were living in Toronto and playing in a band called the Sparrows. In search of success, we all moved to San Francisco at the height of the psychedelic 60s.

We played with the Doors and Janis Joplin, but it didn’t really happen for us. So I left the band to focus on writing songs and – after taking more psychedelics – started calling myself Mars Bonfire.

I finally scraped together enough money to buy a used Ford Falcon and would drive into the mountains and deserts around LA. Those trips in the Falcon provided the inspiration for Born to Be Wild.

I got the basic guitar riff quick, and the lyrics were written chronologically: “Get your motor runnin’, head out on the highway / Lookin’ for adventure, and whatever comes our way.”

One afternoon, I had encountered a thunderstorm so ferocious I had to pull over as the road turned into a river. The sky was ominous, the colour of lead. I was struggling to describe it in words until I remembered the periodic table of elements I’d studied during chemistry class at school.

The term “heavy metals” came into my head, which gave me the line: “I like smoke and lightning, heavy metal thunder!” This was before heavy metal became a music genre.

All the publishers turned the song down. Then Jerry called to say the band were getting back together – as Steppenwolf – and needed songs. I’d just been kicked out of an apartment for playing my guitar too loud, so I made a demo of Born to Be Wild, almost whispering it, with my guitar so quiet it sounded like a banjo.

Luckily, the band heard its potential and my replacement, a 17-year-old guitarist called Michael Monarch, played it perfectly.

I was in the Ford Falcon when I first heard Born to Be Wild on the radio. But after it was used in Easy Rider, as the soundtrack to Dennis Hopper and Peter Fonda riding “chopper” motorcycles, it took on a life of its own.

Thanks to its success, I’ve been able to spend years hiking in the great outdoors and enjoying the freedom I had written the song about. Without it, I’d probably be back in Canada, working at General Motors.

It’s ironic that a song so associated with motorcycles and rebellion was inspired by a medium-sized family car – although I always drove it with the windows down.

When Mars came round to Jerry’s with the demo, no one was home, so he threw the cassette through the letterbox. This caused Tiffany, Jerry’s great dane, to go crazy, barking and scratching.

Mars came to us and said: “I think the dog’s eaten the damned tape!” Luckily she hadn’t. The demo sounded puny, but we thought we could knock it into shape.

I was born during the second world war in what was then East Prussia. My father was killed and my mother escaped the Russian tanks with baby me. We ended up in West Germany after the war.

Given that the country had recently experienced nazism, the song’s message of freedom really resonated with me.

We were rehearsing it in a double garage when, by chance, a record executive called Gabriel Mekler moved in next door. He heard us, produced us and got us signed. But the label didn’t think Born to Be Wild was a single.

They eventually compromised, putting it out on a doubled-sided single with the track Everybody’s Next One, but the radio stations just played Born to Be Wild.

Years after it was used in Easy Rider, I found myself sitting next to Dennis Hopper at an airport and asked how he’d managed to get so many top artists – from Jimi Hendrix to Bob Dylan – to contribute hits to a film soundtrack.

He told me they’d just wanted songs to suit the film, adding that another one of our songs, The Pusher, was perfect for the coke-dealer scene. “We bypassed all the record companies,” he said, “and just rang all the artists – who then told their labels it was a done deal.”

The song changed my life. Twelve years ago, my wife and I sold all our music business assets and ploughed everything into wildlife conservation: helping endangered elephants that were born to be wild.

The song has been used in so many movies that, after 60, we gave up counting. NASA woke up the space shuttle crew with it. And when they landed a spacecraft on Mars, the little robot vehicle came down a ramp to the sound of: “Get your motor runnin’…”