Take your seats, the hippos are about to arrive

You don't go out on the delta before seven. The hippos are making their way back as sun rises and the last thing you want is to run into one of them. A hippo's jaws would flip our zippy little aluminium swamp boat like a pancake.

Mogale joins us at breakfast. He is new to this job but then everyone is new at Xaranna. This island camp in the south of the Okavango Delta, Botswana, the first of its kind to be opened here by &Beyond, had only been up and running for three weeks when I arrived last August. Mogale is our ranger. He and Joseph will be taking us out to see the hippos.

My wife, Kate, has an enthusiasm for birdlife that baffles me, and is excited about seeing fish eagles and lilac-breasted rollers, but we both love hippopotamuses. They are big and ugly and yet cool, too, the way they hang out in water with their eyes poking up like the tops of big fat submarines, their tiny ears flapping.

The hippos used to chill in a pool that is now crossed by swamp boats bringing in supplies and visitors to Xaranna island. Shy creatures, they disappeared after Xaranna opened but four days ago a herd of 12 were found a mile to the north.

Kate and I take our seats in the swampy and Mogale pushes us off. We head down what looks like a road carved through the reeds of the delta. This is the hippo highway, a major channel through our section of the delta that the hippos opened up by swimming through it every evening and every morning in search of food on land. It's easily wide enough for two boats to pass and we know it's deep (more than two metres, says Joseph) because the water is so clear we can see to the bottom.

On our way Mogale explains how the famous delta is fed by rivers that rise in Angola. Millions of years ago geological uplifting across three fault lines prevented the Okavango River ever reaching the Indian Ocean again and the Okavango Delta was born. It's a giant lake that expands and contracts depending on how much water is falling on the Angolan highlands. It is also a famous nature reserve because of the birds and animals attracted to all this inland shoreline.

We take a left-hand fork off the highway and follow a narrow channel pushing through reeds that crowd in on the boat tighter and tighter. After a while, I begin to feel like an American marine in Vietnam, the Hippo Cong might leap out at any moment in ambush. Eventually, Mogale raises the engine out of the water and he and Joseph strain to punt us the last 50 yards. Kate unkindly suggests that if I got out the boat might have better clearance.

"There they are," whispers Mogale and indeed a dozen huge heads, silhouetted black against the morning sun, turn to look at us.

"We keep a safe distance so as not to worry them," Joseph whispers. Safe is 30 metres, any closer and the hippos may start opening their mouths, a prelude to attack. I notice that one hippo head has started to move towards us. From time to time it submerges then pops up closer but a few yards to the left or right of where you'd expect him to emerge. The Cong are checking us out.

"We do this every day now," says Mogale. "The idea is to get them used to us, not to see us as a threat."

I notice that the rest of the herd has clustered closer together while the bull assesses the threat. It's a benign stand-off. After a while we withdraw and Mogale and Joseph abandon our shallow channel entirely to punt us slowly over the top of the water-logged reeds. We pick up a broader channel and try to make it back to the hippo highway, but the engine is choked with weeds. Fortunately we're only a mile from base so a second swampy comes out to help untangle the propeller.

These are the teething problems of a new venture like Xaranna. Everything is new, especially our luxury "tent", which is a really wooden structure with a canvas roof that could be disassembled in a day. Xaranna's nine tents are an experiment in leaving the lightest footprint possible. "We could close the camp and in two weeks you'd never know we'd been here," says Ross, the manager.

Meanwhile, out on the Delta, Mogale is speeding us south to where he's heard there may be elephants crossing. Indeed, when we get to a point midway between two wooded islands, there is a large bull with slender tusks and a younger male. Both are licking their trunks at the greener trees across the water. Our arrival deters them. Joseph points out that the bull is trying to sniff us out. "He can see us but he doesn't know what kind of creature we are."

Eventually, both creatures venture in, lifting their tails to try to keep dry. They go in a long way – I reckon the water comes up 10 feet. We are treated to this sight because we have been still long enough. It seems the elephants are having to get acclimatised to humans round here, too.

Compact Facts

How to get there

Adrian Mourby travelled with Africa Travel (0845 450 1533; africatravel.co.uk), which offers three nights at Xaranna Tented Camp and three nights at Chobe Under Canvas from £2,990 per person, based on two sharing, including return flights with British Airways, accommodation, safari activities, transfers and all meals.