13.

We pushed on further into the jungle, with Innocent telling us the names of the plants and trees. They mostly went in one ear and out the other, if I’m honest, but the most common plant we had to hack through at ground level was a straggly thing about my height, with longish blue-green leaves. Innocent told us the pigment in those leaves was hypersensitive to light, little of which managed to filter through the canopy above.

Though I don’t know what those straggly plants were called I do know the name of the bird responsible for the ‘ka-ka-ka’ noise that erupted close by while Innocent was telling us about the pigment. The kaka bird. Obviously. Later he pointed out an aardvark hole, twice the size of the entrance to the badgers’ set on the north slope of Pitch Hill back home in the south of England, and later still he stopped beside an enormous mound, the surface of which was alive with termites, shimmering in the gloom like petrol on tarmac.

The heat pressed in from all sides.

My shirt stuck to my back, my trousers stuck to my legs, my boots stuck to my feet.

We walked for hours.

We didn’t see any chimpanzees.

But just as I was about to give up hope and suggest we head back to camp and try again the following day (somebody had to crack; I wasn’t too proud to do it) Marcel, who was leading the way, stopped dead mid-machete-swing. We all paused. I heard Amelia beside me take in a breath to ask what was going on, and held up my own hand to shush her, just in time. We all stood still.

‘Bingo,’ sang Innocent.

All at once there was a mighty eruption of shriek-chattering and the canopy ahead of us shook as the troop of chimpanzees we’d walked all this way to see dropped and climbed and swung, hand over hand over hand, from branch to vine to branch, some lowering themselves all the way down to the patchy undergrowth, others ricocheting up into the treetops. Innocent motioned for us to squat down next to him and gave us each a blue paper hospital mask. As I fiddled to put mine on he explained that this troop, led by an alpha male called Bingo, were habituated to humans. The cacophonous display was a greeting of sorts. But although they were used to people, and therefore would tolerate us getting close, that made them vulnerable to catching any harmful bugs we might be carrying.

‘By bugs, you mean pathogens,’ said Amelia. ‘That’s the collective term for viruses and bacteria.’

‘Smart-arse.’ I smiled.

She gave me a questioning look.

‘Just put the thing on!’ I said, snapping the elastic round the back of my head.

Masked, we looked like a gang of surgeons about to perform an operation; if I’d been a chimpanzee I’d have run a mile. But Bingo’s troop didn’t seem to mind. If anything, by the time we’d put on the masks and stepped forward into the trees they’d been cavorting through, they’d calmed right down. Some were still milling about on the ground, but most were back up among the branches, ignoring us.

I’ve seen chimpanzees before, at Whipsnade Zoo, and even though I was only about seven I’d found the fact that they were stuck in an enclosure a bit depressing. This was different. They might have been used to humans, but it felt as if we were visiting them on their terms. They seemed content enough to hang – literally – in the trees around us for the time being, but if they had decided to move off, we had no way to stop them and wouldn’t have been able to keep up with them. That, and the fact that we’d searched for so long to find them, made me really focus on what I was seeing.

The youngster nearest me was picking at the shoulder of the one next to him, parting the long dark fur carefully in search of something or other. He rolled sideways to look more closely at what he was doing, and his short back legs stuck out towards me. I zoomed in on him. How thickly padded his feet were, how pronounced and distinctive the paleness of his face. And those ears. They really did stick out like saucers, comical brackets either side of a serious brow. His fingers mesmerised me most. They were so unhurried and precise. The ape he was grooming had his eyes half closed. The pair of them, sitting right there, not ten metres from us, looked blissfully content.

Having cottoned on to the idea that Amelia knew a fact or two about the natural world, Caleb now started telling her what he knew about chimpanzees. It wasn’t much. ‘You know they’re five to eight times as strong as a man, pound for pound,’ was the best he could come up with. As it happens, Amelia, Xander and I had already speculated about whether that clichéd statistic was true, back at the hotel, and three minutes on Google had dispelled it as a myth. They’re strong, but not that strong. And anyway, looking at these chimpanzees, bumbling about among the vines and sitting placidly together, emphasised their gentleness, not their strength, for me.

I waited for Amelia to correct Caleb, but amazingly she just said, ‘Hmm.’

I fought the urge to say something myself, and won by concentrating instead on what was in front of me again. A female chimpanzee on the ground off to my left had picked up a piece of wood. After inspecting it she brought it down smartly on what I at first thought was a stone balanced on the tree root in front of her. In fact it was a nut. Once, twice, a third time she hit the nut, her face set in concentration, until the shell broke apart, at which point I swear her expression changed to one of satisfaction. I took a photograph of it. Delicately she swept the crushed shell off her anvil-root, retrieved the nut itself and ate it. And then she picked up another nut and repeated the process.

I gaped at Innocent, who smiled proudly. ‘She’s the best at it,’ he said. ‘Also fishing fire ants from a nest with a fine twig … she’s champion of that too.’

‘They hunt meat as well though, right?’ said Caleb.

‘Nuts, fruit, leaves, colobus. They’re as omnivorous as you,’ Innocent replied.

‘We share ninety-seven per cent of our genes with higher primates,’ Amelia said, then corrected herself: ‘Actually it’s between ninety-six and ninety-eight per cent, depending on how you calculate it.’

‘Thanks for clarifying,’ said Xander.

Amelia, missing the gentle sarcasm, took Xander’s words as an invitation to expand, and started telling him about humans and chimpanzees sharing a common ancestor dating back just six-to-eight million years. That seemed a long time ago to me. I tuned them both out. Undoubtedly there was something human about the apes. But it was more complicated than that. Being in the jungle with them filled me with two contradictory emotions. On the one hand I felt as if I was connected, part of something larger than myself. On the other, looking through my zoom lens into the nearest chimp’s black-brown eyes, I felt very, very alone.

I became aware that Innocent had got to his feet. Patience stood up too, beside him. A general restlessness spread among the chimpanzees. Their chatter was more urgent. In seconds they had all moved away. Whether Innocent and his daughter had triggered the change or were responding to it, I didn’t know.

‘Quickly, we must leave,’ he said.

I turned just in time to see Marcel raise his gun to his shoulder. Something – or someone – was moving through the jungle towards us. One figure became two, five, six … nine men at least, half of them armed.