The howler monkeys sounded different from ones I've heard in the zoo. These monkeys made an eerie roaring sound that gave me chills. And some of the frogs sounded like a human being yelping.
I suppose I should tell you more about these tree frogs and howler monkeys, but I would just be cribbing from Wikipedia. I don't know anything about these animals. But I like the way they look, and I love the sounds they make. The next time I go somewhere that has interesting nature sounds, I'm going to go off by myself so that I don't pick up the sound of other people's voices.
More photos and streaming sound files after the jump. (Some of the frog photos were taken by my father.)
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. Come and hear Mark speak at the ALA conference in Chicago on July 1.