The leaves are still dripping from an overnight downpour when Andrés Link slings on his day pack and heads out into the damp morning chill. It’s just after daybreak, and already the forest is alive with hoots and chatter—the deep-throated roar of a howler monkey, the hollow rat-a-tat-tat of a woodpecker, the squeal of squirrel monkeys chasing each other from branch to branch. A strange, ululating chant starts up in the distance, fades out, then builds again.
“Listen!” says Link, grabbing my arm and cocking an ear. “Titi monkeys. Can you hear? There are two of them, singing a duet.” He imitates the high-pitched, rhythmic cry of one of the monkeys, then the other. Only then can I distinguish the two separate strains that make up the counterpoint chorus.
This raucous celebration is the daily background music for Link as he heads out on his morning commute through what may be the most biodiverse spot on Earth. Link, a primatologist from Universidad de los Andes, is researching the white-bellied spider monkey, and he’s on his way to a salt lick a half hour’s walk away, where a group often congregates.