The team opted to paddle the lower section of the river first, and they launched from a downstream access point on May 30. With their Brazilian teammates, they descended 300 miles of the river over 18 days, at one point making a 2-mile portage through the jungle around dangerous rapids.

They avoided the illnesses and mishaps in the rapids that had plagued the team led by Roosevelt and his Brazilian counterpart, Col. Candido Rondon. That trip nearly cost Roosevelt his life, and three of his 19 men were lost in the expedition.

But in many ways, the river was unchanged from when Roosevelt made his descent.

"We saw the same wildlife Roosevelt did - monkeys, caimans, electric eels, cobras, peccaries, tapirs, capybaras, giant otters and even a jaguar," Freeman said. "And the jungle supplemented our trail rations as it did his with piranha, catfish, heart of palm and Brazil nuts."

The expedition team camped at four of the same sites that the president did, and they found that life along the river among native homesteaders, who tap the wild rubber trees and gather Brazil nuts, remains almost exactly as described in Roosevelt's journal.

After completing the lower portion of the river, their Brazilian teammates had to return home. But Schurke and Freeman began making calls to see if they could secure permission to run the upper part of the river as they had planned. They received permission from the Cinta Larga leaders to paddle that section of the river, which passed through land controlled by the tribe.

Their Brazilian teammates delivered Schurke and Freeman to the put-in. The adventurers were about to embark on the upper reaches of the river - alone. That's when they realized they might have a communication problem. They knew only elementary Portuguese, the language of the region, and would no longer have their Brazilian teammates to translate for them.