On one side are the people who believe that the first proto-birds climbed into trees and that, as they glided down, they figured out how to flap.

ECONOMIST: Birds that don't fly may be using their wings to run uphill

"They will just take everything in the landscape and if they destroy the trees and eat the grasses there's no kangaroos, no emus, no small birds if there's no trees, no reptiles, " she says.

BBC: Australia, home to the world's largest camel herd

"We destroy these resources at our peril, " Clinton said during his visit to the park, known for its towering, fog-shrouded mountain peaks, dripping trees and exotic birds.

CNN: Why Do You Think They Call It A Rain Forest?