Looking down at the dark roiling river reflecting the dense jungle, I almost couldn’t believe I was actually here. I have imagined this place ever since I was 11 years old and first spotted the familiar name Roosevelt curiously in the heart of the Brazilian Amazon. Since that time, I have read all about that first scientific expedition 100 years ago down what was then called the “River of Doubt.”

That expedition was led by the Brazilian hero Candido Rondon and co-commanded, mostly in name, by adventurer and past president Theodore Roosevelt. This large expedition faced starvation and many other dangers, and three of its members perished. Near death due to an infected wound, Roosevelt wanted to commit suicide to keep from holding up the rest of the party. He was only prevented by his gallant son. Still, he lost a quarter of his body weight and the expedition is believed to have shortened his life considerably. The river was re-named in his honor. The Roosevelt River is the chief affluent of the Madeira River, which is in turn a chief affluent of the Amazon River, the largest river in the world.

The still remote Roosevelt River hasn’t changed much over the last 100 years. As I stand awestruck at my first sight of the river, a beautiful pair of blue-and-gold macaws come flying down the river squawking, making it seem to me like a wild paradise. But, I’m not naïve. These dark waters hide crocodiles and piranha and the forest harbors jaguars and poisonous snakes among countless other dangers. Ahead of me lies 500 miles of wild river, and though it’s a dream come true I know it will call upon a lifetime of adventure experience to even survive the trip.

In 2013, a longtime friend, Professor Marc Meyers, casually brought up the Roosevelt River while we were sharing some wine over-looking the Pacific Ocean. He was surprised I knew of it.  Marc described his nearly lifelong desire for a scientific expedition on this river, and he wanted me to document it. Marc’s fascinating research focuses on biomimicry, the study of evolutionary design to solve modern engineering problems. And, he focuses on Amazon animals.   I felt the science, history, and environmentalism made this an once-in-a-lifetime adventure, and I immediately joined his effort.

More than a year later, we sat at the remote launch site with the help of GPS, satellite imagery, and locals. The “Roosevelt River Centennial Scientific Expedition” included just Marc, myself, and two Brazilian Army colonels, both with valuable knowledge of the Amazon. Colonel Ivan Angonese, a 20-year jungle veteran, including encounters with the notorious Colombian FARC, and Colonel Hiram Reis Silva, who led military road construction in the Amazon.

The heat was pervasive, and on reaching the river I just wanted to jump in the water but wisely hesitated at the thought of piranha. Hiram then carefully got in thigh deep. This was all the invitation I needed. I spent the rest of the trip up to my nose in the cooling waters whenever possible.

With my engineering background, I wanted to make my own scientific contributions. So, I determined to map a cross section of the river and estimate its flow at points along the way. I also made an extensive guide of the fauna seen on the original expedition to allow comparisons to our sightings.

Mornings started very early–many just shortly after 4 a.m. We had kayaks that carried a small amount of provisions while the supply canoe carried everything else. I referred to them as the “Ferraris and the semi.” My primary role of supplying the muscle power for the canoe was clear to me early-on. I jokingly referred to myself as a “camarada,” the word for the paid peasant paddlers of TR’s expedition. I prepared for the trip by gaining more than 10 pounds, referring to my extra weight as “insurance.” When ribbed by Colonel Hiram, I jokingly shot back that I knew what happened the last time a Brazilian Colonel took an American down this river.

In its upper reaches, the Roosevelt River is narrow, winding and swift. In many places a single fallen tree can stretch across the entire river.  I knew from engineering and being a trained whitewater raft guide that kayaks are faster, more maneuverable, and have shallower drafts. The first day proved this over-and-over again as the heavier canoe required an earlier response, more skill and paddling power to do the same thing the kayaks did with ease. Many times the kayaks would pass right over a shallow rock or branch that then would hang-up the canoe, a dangerous prospect in such a remote place.

We ate gruel for breakfast and either freeze-dried camping meals or a rice, onion, garlic, and dried meat concoction popular with the Brazilians for dinner. This was often augmented with freshly caught fish. I ate twice as much as the others, what Marc referred to as double rations. Still, there was almost no English spoken only Portuguese.

On the third day, we came on Naiveté Falls that Roosevelt described,”It seemed extraordinary, almost impossible, that so broad a river could in so short a space of time contract its dimensions to the width of the strangled channel through which it now poured its entire volume.” We were no less fascinated. The water initially tumbles over a wide waterfall, but then is forced through a constriction that you could jump across. My measurements show that the river is literally turned on its side.  Marc and I found it fascinating that this constriction had not been eroded away, and we collected rocks for testing.

One night, Angonese was on shore catching piranha around me while I soaked exhausted. I felt a twinge on my arm like when you hit your funny bone. My foggy, exhausted mind was slow to register, ELECTRIC EEL! As I took a step toward shore, BAM! I was blasted in the arm by a jolt akin to sticking wet fingers in a live electrical socket. As I tried to take another step, BAM! I was hit with another jolt to the leg causing me to fall back into the river.  Fortunately, I regained my footing and escaped. Eels regularly kill humans here. Yet, for all their years’ experience, the others had never encountered one. I had been there just three days! This started a running joke that Amazon animals “liked” me.

And, I saw a lot of animals the others did not. I stayed up for hours each night doing camera work as the others slept. Plus, I am usually a light sleeper.  Although the jungle is often alive with sounds in the night, an incongruent noise would wake me from a dead sleep. The very first night it sounded like someone was walking up to my tent. I said, “Hello?! Hello?!” But, no one answered. I grabbed for my headlamp and there was a 9-Banded Armadillo feet from my tent. I reached back for my camera, and the animal was gone. Another night, it sounded like a rhino was coming right for me. I exploded out of my tent thinking I was about to be trampled only to come face to face with a Giant Anteater, who was just as startled to see me. He turned tail and fled back into the jungle. It’s important to remember that every animal here earns its place, just this past summer two men were killed by anteaters in separate incidents. Each morning, I felt like the boy with a big tale to tell. Fortunately, each time we would find paw prints or other proof to back up my story.

Each day the river widened, eventually to more than half a mile. After the fourth day, there was little or no flow. This turned my job of paddling the supply canoe 20 to 30 miles a day into a herculean task, like running a marathon every day. Still, everyone contributed and helped each other to make this expedition a success. Angonese was like a super scout. He packed and unpacked the canoe, cleared space for tents, collected firewood, hung the protective tarp for our fire, and caught fish to eat. Hiram constantly poured over printed-out satellite images of our route to determine up-coming rapids and appropriate camps.

It is hard to describe the pervasiveness of insects. The air is literally dark with them around sunrise and sunset, and their buzz sounds like rush hour traffic on a Southern California freeway.  I was what the Brazilians like to call New Blood. For every bite the Brazilians received, I’d receive countless more. My face was mauled daily with photos showing 60 bites or more at any given time on just one side of my face.

The entire experience is surreal. The jungle is so thick it is like a prison. And, the river is the only way out. The jungle doesn’t just go to the water’s edge, it protrudes over and into it. Often, I would paddle for many miles overheating and with legs cramping from being folded up for too long. Yet, there wasn’t a single foot-wide clearing on which to stop and get out for a few minutes rest and stretch. And, the embankments were typically very steep.  Many times, I had to resort to just jumping out of the canoe into over-the-head high water. This made getting back into the canoe without tipping it over a real challenge.

Before I left California, I dreaded the idea of paddling in the rain all day, every day. But, I ended up praying for it when I got to the Amazon. The rain blocked the brutal rays of the sun and cooled me down. Most days it would rain three to five times, sometimes torrentially like one to two inches an hour, but, ironically, during the day, with everything packed in relatively water resistant dry bags, it rarely would rain and the sun would beat brutally down on us. But, the minute everything was unpacked to make camp, a downpour would often ensue.

There was not a single night that I do not remember seeing lightning. Even if the sky was filled with stars above us, there would be lightning somewhere in the distance. It was magnificently beautiful to see these flashes of light backed by dramatic black clouds with the golden hues of sunset filling the rest of the sky.

It rained literally every single night. My greatest hope was just to be able to set-up my tent and try to protect my camera equipment, before it began to pour.  And, it was still miserably hot. I thankfully bought an expensive hot weather tent for this expedition. This allowed me to fold up the rain fly and enjoy the cooling air while being protected from insects, when it was not raining. Then, deploy the rain fly quickly when it started to pour. This inevitably happened just as I was immersed in a deep dream at 1 or 2 in the morning. I slept in just skivvies, still wet from my nightly soaking in the river to cool down. I’d take off the rest of my wet clothes once in the tent and use those as a cooling blanket and pillow. Even if rain did not fall from the sky, most mornings the heavy moisture -laden air in the form of fog, would create rain. This was not a drip here and there, but rather bona fide rain. There was never a time things dried out completely, and the stench of mildew became pervasive.

One night there was a torrential down pour for a couple of hours. I was transferring images to multiple back-up drives to go in different boats in case one of the kayaks or the canoe was flooded or lost. After the rain, it cleared up and there wasn’t a cloud in the dark starry sky. Suddenly, there was a booming clap just on the other side of the river like a bomb had gone off. Often we would hear great trees come crashing down somewhere deep in the veiling jungle. This night, however, the sound was different and seemingly a 1,000 times as loud, like a thunderclap. But, there was no storm. I kept looking out my tent expecting to see a bright flash of light emanating from where the sound was issuing, but there was none. This continued throughout the night. The next morning Marc explained what created the booms. Young trees in their race for survival shoot up to reach sunlight. Then, their trunks expand and strengthen to support their weight. When it rains hard, huge amounts of water race up a tree’s trunk. The additional weight of this water becomes too much for some young trees still strengthening their trunks, and they actually split under the axial compression load. Marc believes this critical failure causes the crack to propagate faster than the speed of sound that in turn causes a sonic boom. I christened this natural phenomena exploding trees.

There is not room enough here to fully describe the piranha attacks, the dangerous endangered Giant River Otters, an encounter while swimming with an aggressive giant crocodile, hostile Indians, the menacing jaguar, an encounter with the dreaded and very poisonous stingray, an aggressive troop of huge wild monkeys descending from above, mishaps in the rapids, and so much more that happened. And, we have only begun to analyze the scientific information.

Yet, it’s worth mentioning our post expedition weigh-in. The Brazilians ribbed me that with all the food I had eaten I’d probably weigh more. This, even after Angonese’s daughter had texted after seeing a group photo on the successful completion of the expedition asking: “What did you guys do to Jeffrey?!”  I had tried to maintain my insurance weight, but paddling that canoe was hard work. And, a scale doesn’t lie. Despite eating twice as much as the others, they lost just three to five pounds each while I lost 20.

The Roosevelt River is an incredibly unique wilderness that will disappear in the next few years without protection. My new ambition is to work with my Brazilian friends to create a World Heritage Site of the entire 500 miles.