On the second day tracking we see the bonobos halt for a midday rest and feed in a nut tree. Luke, Phil and I, necks aching from straining upwards all day, lie down on the spongy forest floor 20 metres directly and unobscured beneath a group of 17 bonobos. Periodically we have to dodge as the bonobos rain down small branches, half-chewed nuts, or the occasional and well aimed piss from their lofty perch. For a whole two hours we lie there, transfixed by their tranquillity. Three mothers are in a tight bundle together, quietly and intimately grooming their infants, regardless of which infant belongs to which mother. What must be in the mind of those infants, in such a press of maternalism and being tended to by not just one mother but effectively all of them? The feelings of togetherness, warmth and security, and -- dare I say it -- love, those infants feel must be immense. No wonder bonobo society, soaked in such nurturing, is matriarchal.

Sadly the day arrives when we must leave our bonobo haven. We wave farewell to the gathering of villagers on the riverside. Once more we are afloat in our trusty pirogues, this time going with the flow of water, back down the river of man -- out of the time tunnel -- to resume once again our modern day lives.

We have a full moon now to guide our night-time stretches. By its light on the third night I am sitting on the bow, head brimming like the water around me with the wonder of the experiences of the past few weeks. A poem comes to mind and I recite it out loud, though not so loud that those back in the mozzie nets hear me and think I've lost my marbles.

It's from T. S. Eliot's "4 Quartets":

We shall not cease from exploration
and the end of all our exploring
will be to arrive where we started
and know the place for the first time.
Through the unknown, unremembered gate
when the last of earth left to discover
is that which was the beginning.
At the source of the longest river
the voice of the hidden water fall
and the children in the apple-tree
not known, because not looked for
but heard, half heard, in the stillness
between two waves of the sea.

The bonobo. The children in the apple tree indeed. And the river that swallows all rivers, the mighty Congo, is bearing us onwards ... onwards from what feels to us a source of light rather than a heart of darkness.

And ahead on the river the rapids, swamps, cataracts and whirlpools, all metaphorically being borne with hope by humanity for that potential destination -- one day -- of an oceanic maturity.