From a young age, Roosevelt’s sense of manhood was tied to physical challenges. It became habitual for him to seek out such challenges when confronted with setbacks in life, and exploration held a strong appeal for him. A naturalist at heart, Roosevelt was genuinely interested in plant and animal species. Thus, he took his South American expedition seriously, with Millard presenting Roosevelt’s conceptions of masculinity and endurance playing a key role in his attitude and behavior throughout the expedition.

The suggestion to change the itinerary from one well-navigated river to an unknown one appealed to Roosevelt, revealing his taste for endurance and adventure. Unlikely aware of the dangers in the rainforest, Roosevelt wanted to contribute to science. His attitude was humble and committed: He did not challenge Rondon’s command of the expedition, and despite his status, he was not above menial tasks, such as washing clothes and helping out at the campsite. He was quick to run after the murderous de Lima to prevent him from killing another Brazilian despite the risk to himself. In another example, he jumped into the river to help the group rescue one of their boats caught on the rocks. He did this despite having a bad left leg and managed to cut his right leg on the sharp rocks.