There was one thing the wildlife guide in Zimbabwe had forgotten to mention.
"Apparently when elephants twitch their ear, it's a sign they're becoming agitated," photographer Ken Duncan recalled. ''So when it starting twitching I thought "isn't that cute' and made doubly sure I was getting the images.
"Next thing this bull elephant was charging at me. We were on a grass island on the Zambezi River and the guide had stressed to me that whatever happens, don't run. So I was backing off trying to stay calm when I fell over. Suddenly all I could see was sky, grass and water flying over me and hear this angry elephant trumpeting.
"It flashed through my mind that I could be in real trouble here, but then I see this hat fly through the air and I could hear the elephant retreating. That's one of the tricks the guides use ... they throw their hat at the elephant and it often scares them away. Doesn't always work though, they say."
The end result? One of his favourite images of all called The Power of One.
Duncan, the NSW Central Coast photographer best known for his stunning landscape images, was telling the story behind some of the pictures he selected in his new coffee table book called Walking in the Wild (RRP $60) which hits the stores this week.
The big difference with this one of course - he's done "about 70" coffee table books with sales topping three million, and countless calendars - is that it's his first based on animals and has been more than 15 years in the making.
"I've always been a landscape photographer who has had a keen interest in animals," the nearly 66-year-old explained. "So for years I've had people who have seen my wildlife images asking me to do a book on them, but I'd never got around to doing it. My wife Pam has always been pushing me to do it too.
"Then when COVID came, I thought I can't go anywhere anyway, so why not go through all these images and see what I've actually got? I guess I'm trying to take people on safari in their own lounge rooms."
Walking in the Wild - all 168 pages of it - was born. And he's delighted with it.
It took many hours of sorting through pictures, numerous memories triggered, some hard decisions on how to cut thousands of images down to "120 or so" - a job that became even harder as he narrowed it down to the final cut, until finally ... job done.
"I love the big animals, so a picture of lions or elephants had to be spectacular to make it. Then I wanted animals from different places, so I've got pictures from China, Brazil, Canada, Finland, Africa, India, Australia...
"I also wanted different animals ... black swans in China for example. We were feeding them and then out of nowhere came all these brightly coloured fish to eat too. I love that shot, this swirl of colour.
"And I've got a shot I really love of a polar bear hugging a sleigh dog in Canada. I saw them playing and thought oh no, this is going to end badly. But they played for 20 minutes and had a great time, mutual respect, and the bear gave the dog a hug as it headed off. Incredible."
Don't ask him for his favourite, or he'll invariably say "the next one".
Reading between the lines though, the picture of the elephant he upset on the Zambezi, which he has called The Power of One, is right up there.
Some took more work that others. A picture of an eagle in Finland, for example, meant sitting in a hide for 10 hours in -30C temperature.
And there's no doubt at times it has been extremely dangerous. The elephant charge, for example, isn't unique. He's also had the thrill - is that the word? - of having a lion and a rhino bearing down on him at different times.
"It's partly my fault," he admits. "In the early days I was obsessed with the wide angle image of a big animal in a big landscape, so I'd have to get up close to get what I wanted. But the shots you'd get, when you blew them up big, were really stunning. Like the image of a leopard on the cover, it's so sharp."
But it's funny how being chased by deadly animals can change your view.
"A longer lens is not a bad thing," he now concedes, slight hint of chuckle. "Adjusting the focus on the run ... you feel immense satisfaction when you get that right and nail the shot."
The other thing he acknowledges is that he has come to understand the animals more over time.
"How they're feeling, sensing which way they might move ... I didn't have that in the early days."
Which brings us to a mental state he gets in when taking pictures: 'entering the zone' he calls it.
It's important to him because, by his own admission, he feels inadequate as a photographer. Something that 70 books, numerous calendars and three million sales hasn't changed.
"I was on a safari bus in Zimbabwe with a group of people and none of us were getting the shot we wanted. Everyone was getting frustrated, you could feel it.
"The guide said you have to have patience and to take pictures with love.
"I asked him later what he meant. He said we had to love being in Africa, love being in the moment doing what we were doing. He said don't worry if the shot's not there, let it happen. The pictures will come.
"So I try to get into that zone when I'm at work.
"The first time I tried it was on that bus - and all the good shots that started coming later that day seemed to be on my side of the bus, right in front of me. So I've always tried to calm down, to be at peace."
"I guess you could stay like that forever," I replied.
"No, three weeks and you've had enough," he says, breaking into a laugh.