"I had made a terrible mistake..." wildlife biologist Steve Boyes says, describing the day when he and his research assistant were thrown off their mekoro into the waters of the Cuito river by an angry hippopotamus.
When he saw a rustling in the reeds, he immediately thought they were approaching a crocodile and headed to deeper water, where crocs aren't as powerful.
But he assumed wrong. By the time one of the team members shouted "kubu!”, ‘hippo’ in Setswana, the ill-tempered mammal had already crushed the canoe with its powerful jaw.
Steve and his assistant managed to swim to the riverbank safely, but the two massive holes pieced through the solid 500kg mekoro served as a reminder of the wilderness territory they were in.
Steve led a 35-person team of explorers and scientists across 2 540km from the source of the Okavango delta in the Angolan highlands to its desert estuary in Botswana in 5-metre, flat-bottom mekoro, or canoes - an expedition which qualified him as a contender for the 2015 National Geographic Adventurer of the Year, with the winner set to be announced in February 2016.
NatGeo named him the 'Wilderness Protector' and the 36-year-old nature-lover is the only adventurer from Africa in the group of finalists.
When the hippo bit through his boat, he was a month into his four-month-long expedition, which he hopes will make a convincing case for the forests, floodplains and rivers of this area to be officially declared as Africa’s largest wildlife reserve.
The Okavango Delta in Botswana was declared a UNESCO World Heritage Site in 2014, but Boyes says that as long as the rivers that feed the delta remain unprotected, the delta is at risk.
NatGeo describes it as an "unprecedented international conservation effort that would ensure the preservation of the entire Okavango catchment".
On the expedition, the team of researchers, area experts and data collectors ventured into territory that had never been explored before. They were the first people to explore the source of the Okavango delta and document their findings in this life-giving southern African artery from its spring in Angola, through Namibia and finally to Botswana.
They spent the first nine days of the expedition harnessed to their half-tonne mekoro, dragging the boats over dry land where the river channel was too narrow to pass through.
"We anticipated the trip to the source to take no longer than 21 days," Steve said. They arrived there six weeks later, 21 days behind schedule.
"Police helicopters and the Angolan government were resupplying us so we could make it to the river - we wouldn't have been able to do it without the support of the Angolan government".
Once on the river, 15 team members joined him in six mekoro. Their river journey wasn't any easier as they were constantly faced with the typical challenges one comes across when you venture into uncharted territory. Apart from the hippo, they had to row alongside crocodiles, drift past herds of elephant - the largest remaining population of elephants in the world.
"At one point, we encountered a herd of about a thousand buffalo," Steve recalls.
Many times their boats would capsize because of the obstructive fig tree roots lying just below the water's surface. But the technology was never damaged says Steve. "The waters in these rivers are so pure, it has no conductive power. You'd drop your laptop into the river and it wouldn't even know it's under water!"
The expedition's dangerous edge had a few upsides too.
On the trip Steve and his team came across hundreds of new birds, fish, insects and plants. Many of these newly-documented organisms are still being accessed before they will be officially declared.
In total, they recorded 11 000 wildlife sighting on their live stream app on the expedition - that's more than 32 000 individual animals.
Steve says they chose to broadcast their expedition in real time in order to save time. "We can't be conservationists and hide away with any kind of data, because action has to happen now," he says. For Steve gathering all of the scientific data they did, and then hiding it at a university waiting to be published would have been counterproductive.
The expedition was streamed on the interactive page intotheokavango.org.
"We got to share the new experience with people around the world. School kids in Canada as well as our family members could be on the expedition with us. We never considered the research our own - it belongs to the Okavango delta. We wanted to make a statement for conservation."
Steve says he strongly believes that this 'open science' is the way to raise awareness about conservation.
"Very few people get to walk the moon - but with technology, we all get to share the experience," he says. "And that's how you create awareness and open the world to everyone."
Despite the setbacks early on, Boyes and his team made it to the delta on 18 September 2015.
The team's heart-rates, which were monitored on their live streaming devices, averaged a whopping 135 beats per minute throughout the trip - the norm should be 100.
Evidently, their hearts were in it.
VIEW MORE PHOTOS OF THE EXPEDITION HERE: The Wilderness Explorer
View the NatGeo 2015 Adventurer of the Year motivation for The Wilderness Protector: Steve Boyes here:
In conversation with the Wilderness Protector - Steve Boyes:
What is the next adventure?
I am going back to the source [of the Okavango] again soon for six shorter expeditions to conduct more targeted biodiversity surveys. This time we will be exploring the area on motorbike, mountain bike and using air travel.
In 2017, I want to do a similar expedition and go to the source of the Pondo river.
What would you do differently?
Took us years to get ready for this. Before we went we thought of everything, and tested everything. There wasn't really anything we could have changed.
But we wouldn't have been able to do it without the help of the people and government in Angola. National Geographic opened all the big doors with government, politicians and people. But I saw during this trip that the Angolans are ready for a new beginning.
How can other people be part of an expedition like this?
There is a luxury option available for paying tourists. Tourists can go on an expedition led by Steve Boyes across South Africa for around R250 000 ($18 000) for 9 Nights and 10 Days.
There is also a 18-day expeditions option in a private jet that would cost you roughly R940 000 ($67 000).
What would winning the Adventurer of the Year title mean to you?
It would set the benchmark for trans-boundary conservation.
Winning this title would also mean so much for South Africa - it would get the young ones inspired. Plus it is incredibly important for the team to get the recognition for their hard work.
Who would you vote for as the Nat Geo 'Adventurer of the Year'?
The Solar pilots. Swiss pilots André Borschberg and Bertrand Piccard successfully flew across the Pacific without using a drop of fuel. Instead, their five-day flight, the longest continuous flight ever and part of their round-the-world journey, was powered by the sun.
What advise can you give prospective adventurers/explorers?
It's not necessary to have subjects like geography, science, maths. You have to have passion.
You can use your expertise - whatever it may be - to benefit it conservation if you have PASSION.