Girls from the village of Sawré Muybu play near the banks of the Tapajós River in northern Brazil. The area, and the lifestyle, are threatened by a massive hydroelectric project. Mauricio Lima for Al Jazeera America

Juarez Saw Munduruku tilted his head back and let out a lilting, high-pitched laugh. Photographer Mauricio Lima and I had already spent several days living with his tribe deep in the Amazon, but only now had the tribal leader explained some important rules about how to avoid some of the rainforest’s more dangerous inhabitants.

The villagers of Sawré Muybu, who are fighting Brazilian government plans to flood much of their historic lands as part of a $9.9 billion hydroelectric dam project on the River Tapajós, bathe in a sheltered brook at the foot of a gentle hill. It was not until we had made a couple of visits, however, that Juarez revealed the path that leads there is frequented by deadly snakes everyday after 5 P.M. Worse still, after 6, alligators return to sleep in the brook.

On previous evenings, captivated by the scene of the children playing in the water, both Mauricio and I had stayed much later as darkness had approached. My colleague even persevered with the evening visits after Juarez’s advice. The tribal leader, for his part, found our reaction in the face of the jungle to be hilarious.