Dozens of times every day for eight days we wade across & along the meandering river. Tapir tracks on every beach. A bit further downstream, with muddier banks, we also see an abundance of capybara tracks. Jaguars have walked on most of the beaches. On two occasions we even see tracks of a mother with its young (its tracks less deep in the sand). We regularly see tracks of ocelots and other small cats, of peccaries, deer, cayman, turtles. We run into two families of giant river otters: together thirteen animals along this one small river, of a Peruvian total of only four hundred! Day after day we hear the calls of razor-billed curassows. We see six species of monkies, amongst which no less than four different groups of spider monkies. 


This is a beautiful forest. But how can we be sure that this is an unspoilt forest?  By compiling our own observations from four expeditions.

Changed since our first expedition in 1995:

This time we didn’t meet any human beings: no illegal loggers or gold miners, no eccentric farmer from Arequipa who had fled after a killing, no extended family group of Machiguengas who had established themselves at the Rio Azul, filling up the vacuum left by the Harakmbut, who were lured away by the Dominican mission.

Four groups of spider monkies that do not seem bothered at all by our presence. These are the first prey animals to disappear under even the slightest human hunting pressure. Not just because it takes seven years before a female has grown to maturity and will try to raise her first baby, but especially because spider monkey meat is highly prized. As a Harakmbut elder told us: “Spider monkey is delicious, so tender, almost as tasty as human.” Spider monkies all around is a guarantee that big seeds with a lot of pulp are being spread. This guarantees the survival of many tree species & is vital for the overall health of a primary forest.

All those loud razor-billed curassows! During our previous three expeditions we had not seen nor heard a single one and now their deep booming notes can be heard at nearly every curb. They are safe again in the dense undergrowth of the river banks. Like the spider monkies, the razor-billed curassows are prized for their meat. Their presence is further proof that there is absolutely no human hunting pressure.


Is it fair to count the crested eagle as a proof this forest is unspoilt? After the harpy eagle, the crested eagle is the biggest monkey- eating raptor of the jungle! A top predator, just like the black caymans, electric eels, giant river otters and jaguars we have seen.  Every one of them proves that this system is intact, not touched by us humans, by the opportunistic, super predators, hunters, gatherers we are. Well, no: this does not count as another proof: a crested eagle is always hard to observe. The fact we saw one this time was pure luck. We will only make a twitch on our personal lifelists, just to make other birders envious.


It was a privilege to spend ten days in their forest with six Harakmbut. No worries, easy going, only a few minutes of discussion every now and then, no action without necessity. Just cutting down some balsas for two rafts, since after two days of carrying our supplies over the mountain range to get to the Azul basin it was no fun anymore. From then on they leisurely rafted down the river, stopping where the fishing seemed good and regularly venturing with a machete into the forest to harvest some bananas: still visible proof that this region used to be inhabited. If those two weird biologists really want to walk down the whole river, they are more than welcome to do so. Every now and then they walk along with us for an hour or so. At noon we all cool down in the river together, followed by eating rice with fried piranhas and catfish in the shade. All was a matter of course. Making camp at night? What for? They only do this, within a few very efficient minutes, on this one occasion in the middle of that night when it started pooring with rain. The other nights they sleep on some plastic and blankets, just outside our modern small expedition tents. Only this one night full of thunder and lighting we slept as dry as they did under their plastics. All other nights we gringos were sweating like hell in these enclosed small tents. Next time we will also be more relaxed, bringing just a mosquito net and our own piece of plastic.


They clearly stated that we didn’t walk down the Rio Azul, the Blue River. “Ridiculous Spanish name for our Isiriwe,” Mateo said.  Also, because most of the time the Isiriwe is just as muddy as all other rivers around here. Mateo knows: his mother was born at the Isiriwe, in a time when missionaries, oil barons and biologists did not exist.


Piet van Ipenburg

John Smit