Meet the hoatzin, the Amazon’s feathered equivalent of a compost heap. This pheasant-like oddball ferments leaves in its oversized crop, burping methane like a cow and earning the title of the world’s stinkiest bird. With clawed wings and a 64-million-year-old lineage, it’s a prehistoric weirdo that smells so bad it scares off hunters—but not the brave Great Black Hawk. If you thought your morning breath was bad, wait till you meet this guy!