Amazon Adventure

Hal sat on the head of a stuffed crocodile in the lobby of the Quito Hotel and cleaned his gun.

Plot
Teenagers Hal and Roger Hunt accompany their father, the animal collector John Hunt, on an expedition to the Amazon River to explore the Pastaza River, an uncharted tributary of the Amazon. As they prepare to depart from Quito, Ecuador, their fears are hightened by anonymous threatening telegram and a suspicious stranger Hal encounters on the streets of Quito, and promptly names "Croc."

Animals Collected

 * Iguana
 * Anaconda
 * Boa constrictor
 * Tapir
 * Vampire bat
 * Marmoset
 * Jabiru
 * Wood ibis [later eaten by the anoconda]
 * Basilisk
 * Electric eel
 * Giant anteater
 * Sloth
 * Armadillo
 * Amazon deer
 * Two jaguars

Real Life Adventure
An actual animal collector, Roderick Cambell, that Willard Price accompanied on an expedition in the Amazon, appears to have been the inspiration for John Hunt. In his non-fiction book, The Amazing Amazon Price describes the following incidents, which all appear in Amazon Adventure:
 * A man getting stuck on a tree branch as his canoe passes under it
 * Floating down the Amazon on a floating island
 * Starting a fire without matches, by using a camera lens
 * Steps for creating a shrunken head
 * Meeting a Brazilian settler whose farm has been raided and burned by bandits