Dolphins, alligators and tribes in Brazil’s Amazon fores

In this Oct.12, 2017 photo, a sunset in the Amazon rain forest is seen from a tributary of the Rio Negro outside Manaus, Brazil. Boat travel is common throughout the Amazon basin, both for forest dwellers and tourists.

            By PETER PRENGAMAN        Associated Press

 MANAUS, Brazil — The warning from our guide made clear that this “forest walk” would be anything but a leisurely stroll.

“Look before grabbing any branches because the ants bite. You will be in pain for 24 hours,” said Jackson Edirley da Silva, wearing a bright yellow shirt and rubber boots. “And watch where you step. You don’t want to get bitten by a snake.”