ScienceActuallyHoatzins have an enlarged crop that acts as a fermentation chamber, breaking down the leaves they eat. This process produces foul-smelling bacterial vapors that are similar to cow manure - hence their nickname ‘stink bird’.
The hoatzin is the only bird with a digestive system that ferments vegetation as a cow does, which enables it to eat leaves and buds exclusively.
Hoatzin | bird
hoatzin, (Opisthocomus hoazin), primitive chicken-sized bird of South American swamps, principally in the Amazon and Orinoco river basins. The young possess two large claws on each wing, a trait that has led some scientists to link the species with the fossil Archaeopteryx of the dinosaur era. The hoatzin is the only bird with a digestive system that ferments vegetation as a cow does, which enables it to eat leaves and buds exclusively. Hoatzins feed on swamp plants, grinding foliage in a greatly enlarged crop (not the gizzard, as in other birds). Adults can fly clumsily for short distances, but they